Relationship Between Time Overrun and Completion Cost of Construction Projects

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Published on International Journal of Economics & Business
Publication Date: December, 2019

Yusuf, Anthony Olukayode
Department of Quantity Surveying, Faculty of Environmental Design and Management
Obafemi Awolowo University
Ile-Ife, Osun State, Nigeria

Journal Full Text PDF: Relationship Between Time Overrun and Completion Cost of Construction Projects.

Abstract
Nigerian construction projects are almost synonymous with time and cost overruns, and many researchers have opined that the completion costs of construction projects are affected by time overrun. However, the extent of this cause and effect relationship is not known. These identified issues have invoked concern and caused inefficiency of project delivery by the Nigerian construction industy. Hence, this study assessed the effect of time overrun on completion cost of construction projects with a view to ensuring that construction projects are delivered to scheduled time and estimated budget.The research was carried out using structured questionnaires to collect both primary and secondary data (cost and time data of executed projects). Respondents were construction professionals chosen randomly based on their involvement in the construction industry. The data collected were analysed using descriptive statistics such as percentile, relative importance index and regression.The results showed that clients are the most frequent source of time overrun followed by contractors. The study also showed that clients are the sources of time overrun with the most significant impact followed by consultants.The client related factor with most occurence and most significant impact is owner’s interference, for consultants it is discrepancies between contract documents, for eternal factors it is contractual claims. Those of contractors are insufficient number of staff which is the most frequent and inadequate construction planning and mistakes during construction which are most significant. Finally and most importantly, the effect of time overrun on completion cost of construction project was evaluated to be: C= -97777230.963 + 29025400.854T – 780609.663T2 + 5652.411T3, R= 0.719, R2= 0.517. C=Cost Overrun in Naira, T=Time Overrun in weeks. Hence, time overrun majorly caused by clients, consultants and contractors must be prevented by these project participants so as to keep cost overrun at bay

Keywords: Construction projects, time and cost overruns, construction industy, consultants and contractors.

1. INTRODUCTION
1.1 Background to the Study
The construction industry is the tool through which a society achieves its goals of urban and rural development (Ashwini and Rahul, 2014). It is also identified as an essential sector for any country as it provides necessary requirement for improving the standard of life (Abedi, Fathi and Mohammad, 2011b). Construction is a vast industry which provides various projects for residential, industrial or commercial facilities (William, 2010). Hence, huge sum of money are expended for providing new facilities or retrofitting existing facilities to satisfy the needs of society for shelter and economic growth (Abediet. al., 2011b). As defined in developed countries (Hillebrandt, 1985), construction is considered unique in that it can stimulate the growth of other industrial sectors. Hence, improving construction efficiency by means of cost effectiveness and timeliness would certainly contribute to cost saving for the country as a whole. Construction has been described as a risky industry with uncertainties due to many internal and external factors that influence the construction process (Ashwini and Rahul, 2014).
According to Abedi, Fathi and Mohammad (2011a) a construction project is commonly acknowledged as successful when the aim of the project is achieved in terms of predetermined objectives that are mainly completed the project on time, within budget and specified quality in accordance with the specifications and to stakeholders’ satisfaction. Functionality, profitability to contractors, absence of claims and court proceeding and “fitness for purpose” for occupiers have also been used as measures of project success. Ismail, Aftab, Ade and Nor (2013) stated that cost is among major consideration throughout the project management life cycle and is considered as prime factor for success of any project. Al-Momani (2000) opined that construction time overrun is a critical function in construction of public projects which has been of great interest to construction researchers but has not been well understood in the case of public building projects. Time overrun in construction projects causes multitude of negative effects on the projects and its stakeholders. Therefore, this aspect has been constantly investigated by researchers across the world with great enthusiasm (Dolage and Rathnamali, 2013). Time overrun reduces the efficiency of available economic resources, limit the growth potential and reduce competitiveness of the economy (Singh, 2010). Adam, Josephson and Lindahl (2014) claimed that due to the magnitude and frequency of these time overruns, they have come to pose a significant financial risk to both clients and contractors. Ameh and Osegbo (2011) stated that time overrun affects the project owners, contractors and other project participants and that project owners may be affected through loss of benefits that could have accrued from the completed facility, while contractors may have to spend more on labour and plant, pay penalties as per contract or even lose other profitable contracts because resources for the next job are tied upon delayed projects. In the same vein, Ashwini and Rahul (2014) also emphasized that time overruns are always measured as expensive to all parties concerned in projects and very often it will result in clash, claims, and total desertion and much difficult for feasibility.
While discussing the need to assess the causes of time overrun, Sweis (2013) observed that as a major sector of a nation’s economy any ups and downs in this sector will immediately be reflected in the national income. According to Saleh, Abdelnaser and Abdul (2009) the impacts of time overrun in construction projects are loss of interest by stakeholder, blacklist by authorities, waste of money and time and declination of reputation. Hamzah, Khoiry, Arshada, Tawil and Che (2011) mentioned that time overrun often causes disorder in workflow and reduces productivity.
According to Ashwini and Rahul (2014) about 57% of Indian construction projects are experiencing time overrun. In Jordan, Sweis (2013) opined that most construction projects in developing countries are characterized by overrun in time and that time overrun is a very frequent phenomenon and is almost associated with nearly all projects in the construction industry. Sweis (2013) further stressed that time overrun is considered to be one of the most recurring problem in the construction industry as 65% of the projects understudied has time overrun. Similarly in a study conducted by Dolage and Rathnamali (2013) it was revealed that 80% of construction projects are not completed within the agreed contract period. These led to researchers submission that time overrun in construction projects has become one of the commonest problems in the construction industry that causes multitude of negative effects on the projects and its stakeholders. The history of the construction industry worldwide is full of projects that were completed with significant time overrun and the problem of time overrun is of international concern (Ameh and Osegbo, 2011). Adam et. al. (2014) states that for decades, the construction industry has been characterized by completion times reaching further than what was set out initially. Ismail et. al. (2013) described time overrun in the construction projects as one of the chronic problems facing the construction industry in recent times. Adam et. al. (2014) also considered time overrun as having long been regarded a common occurrence. Delays occur in most construction projects, either simple or complex (Ashwini and Rahul, 2014). It is therefore evident that time overrun has been identified by numerous researchers as a major problem in the construction industry hence it is important to investigate its effects on cost of construction.
Ibrahim, Roy, Ahmed and Imtiaz (2010) stated that in Malaysia very little research has been carried out by academics and practitioners on problems faced by construction industry, more specifically there is lack of investigation on construction cost factors (Toh, Ali and Aliagha, 2011). The project time overrun problem is faced by numerous countries and the study on the causes of these problems is also conducted such as India (Singh, 2010), Jordan (Sweis, Hammad and Schboul, 2008), Nigeria (Aibinu and Odeyinka 2006), Saudi Arabia (Assaf and Al-Hejji, 2006), Hong Kong (Tommy, Ivan and Karen 2006), Egypt (Mohammed and Tarek, 2013), Malaysia (Hamzahet. al., 2011). There appeared to be a consensus among researchers that time overrun has adverse effects on construction processes and project delivery but few if any has taken a critical look at those effects.
While assessing the factors causing time overrun, Sweis (2013) opined that construction time overruns are integrated parts, none of them can be divided from the other, and this is clearly seen by the costs construction time overruns leave behind. Ramabodu and Verster (2010) identify critical factors that cause time overruns in construction projects as changes in scope of work on site, incomplete design at the time of tender, contractual claims (extension of time with cost), lack of cost planning and monitoring of funds, variations and additional works. Ashwini and Rahul (2014) stated that time overrun result in clashes, claims, total desertion and much difficult for feasibility and also it slows the growth of construction sector. Time overrun results in the growth of adversarial relationships, litigation, arbitration, cash flow problems and a general feeling of apprehension between project participants (Ameh and Osegbo, 2011).

1.2 Statement of Research Problem
According to Abediet. al. (2011b) time overrun may occur in any construction project and the magnitude varies considerably from project to project. Some projects are only a few days behind the schedule: some are over a year. So it is essential to define the actual causes of time overrun in order to minimize and avoid it in any construction projects.Ashwini and Rahul (2014) proposed that to improve the performance of construction projects we need to control the single most important factor of time overrun. Shebobet. al. (2012) pointed out that it is necessary to identify the actual causes of time overrun in order to reduce the impact of time overrun in any construction project. Sweis (2013) revealed that several studies have addressed many different factors that cause time overruns in different types of construction projects but a new type of construction projects has not escaped the overwhelming ghost of time overruns. While considering time overrun, Ameh and Osegbo (2011) buttressed this by revealing that volumes of articles have been written in an attempt to eliminate or minimize construction time overrun along with its debilitating effects on project owners, contractors and consultants, but the issue remains unabated. Also, multiple efforts to create a statistical model to help adjust the floats and budgets of the planning schedule have been conducted in recent studies, only to emphasize the effect time overruns has on every angle of the construction project process (Cited by Sweis, 2013). Ijigah, Ogunbode and Ibrahim (2012) suggested that there an acute need to keep project time within limit to avoid time overrun
Despite the available literature and solutions proffered to time overrun, much of these contributions only addressed the identification of the causes of time overrun little attention have been paid to assessing the effects of time overrun on the cost of construction project especially in Nigeria. Hence in order to bridge this gap, this study will answer questions on the effects time overrun on cost of construction projects. In this regard, the following questions came up:
1. What are the sources of time overrun on construction projects?
2. What are the factors influencing time overrun on construction projects?
3. What is the relationship between the factors influencing time overrun and the time overrun of construction projects?
4. What is the effect of time overrun on cost of construction projects?

1.3 Aim and Objectives of the Study
The aim of this study is to assess the effects of time overrun on construction cost in Lagos State with a view to ensuring that construction projects are delivered to scheduled time and estimated budget.
The objectives of the Study are to
1. identify and assess the sources and causes of time overrun on construction projects in Lagos State Nigeria;
2. identify and assess the factors influencing time overrun on construction projects in the study area;
3. evaluate the effects of time overrun on cost of construction projects.

1.4 Need for the Study
Completion of projects behind schedule has been one of the recurring problems in the construction industry which result in diverse but adverse effects on the outputs and impacts of the industry in national development. Failure to achieve targeted time results in various unexpected negative impacts on projects. Chan and Kumaraswamy (1997) stated that a project completed on time within budget and to the specified quality standard is considered successful. According to Odunsami and Olusanya (2000), as a result of persistent increase in contract sum and extension of project time in Nigerian construction projects success as opined by Chan and Kumaraswamy (1997) is yet to be obtained.There is hence a need to ensure timely completion of projects to prevent these negative effects. A client wants value for his money while other parties in the industry want to maximum profit. It is therefore necessary to look at the factors that influence one of the major determinants of a successful construction project; time, how these factors influence each other and then see how the effects of this factors on time affect the completion cost of projects. This study will contribute to the current body of knowledge pertaining to the impacts of time overrun on completion cost of construction projects. It will also provide some reasonable mechanism necessary to minimize those impacts in construction operations and will be if value to the academics and industry alike.

1.5 Scope and Delimitation of the Study
This research work will investigate the effects of time overrun on completion cost of construction projects. These construction projects include only public and private building projects. Since construction fall into different categories such as building, civil and industrial engineering among others, the study will focus on building projects. This is because this category of projects are the most common projects executed in Nigeria and data on them are well documented and are also easily retrieved (Aje, Adedokun and Ibironke, 2014). The study will be carried out in Lagos state Metropolis. Lagos is located in the South-western part of Nigeria. Being a former Federal Capital and now the commercial nerve centre of the country, Lagos hosts many of the reputable construction companies operating inNigeria. Lagos is listed as one of the 25 megacities of the World with an estimated population of about 17million in 2007 and a growth rate (3.2%) which has an attendant pressure on its infrastructure. There are numerous construction projects in Lagos executed by both the private and public sector to meet the housing, economic and infrastructure requirements of the emerging megacity (Ameh and Osegbo, 2011). The choice of Lagos will benefit the study because it will permit the sampling of a large population of technical and management staff of construction firms.

2. LITERATURE REVIEW
2.1 Introduction
The previous chapter has briefly discussed the rationale behind the study, including the need to examine the effects of time overrun on cost of construction projects. It also discussed the need for the study, aim and objectives of the study.
This chapter will discuss the various literature concerning the concept of time overrun, sources of time overrun, factors influencing time overrun on construction projects, and the effects of time overrun.

2.2 The Construction Industry
Al-Momani (2000) identified the construction industry as one of the vital sectors in the development process. According to Amoa-Abban and Allotey (2014) the construction industry plays a very significant role in the socio-economicdevelopment of the nation. The interrelationship between the construction industry and the broader economyemanates largely from three of the industry’s characteristics namely: the public sector client as its major client,its large market size with the ability to produce investment or capital goods which contribute significantly to thenational GDP, and as a major source of employment both directly and indirectly by its multiplier effect. The construction industry is generally responsible for the physical development or the transformation of the environment (Hillebrandt, 2000).The built environment is vital to social-economic development of a nation and its contribution are crucial and a focus of any nation’s economy (Ijigah, Oloruntaba andMohn,2012).The construction industry is a major player in the economy, generating both, employment and wealth (Abediet. al., 2011a).
According to Shanmugapriya and Subramanian (2013) large scale development activities are taking place in Indian construction industry and it has assumed the proportion and responsibilities of a big business and is closely associated with the nation’s economy. A large number of building projects and new infrastructures are being built on a great scale which contributes to the economic growth of country. Apart from the economy aspect, the speed with which construction is carried out is also an important factor. Poor project performance in terms of achieving project objectives has remained the baneof most private and public projects inNigeria (Adindu and Ibironke, 2012).
The need to understand the concept of construction risks anduncertainties, their constituents and their impact on contract timeand cost objectives of building contracts in Nigeria is pertinent (Adindu and Ibironke, 2012). Several finding of studies shows that the industry has reduced in its contribution to the national economy and its performance in terms of cost and time of project (Oladipo, 2006; Oladapo, 2011) although the research by Otti (2012) revealed that they is an improvement in the performance of the construction industry from 2008. These are due to better project management, improved contract method and the involvement of clients and contractors in project delivery (Ijigah, Ogunbode and Ibrahim, 2012).
A construction project comprises of two distinct phases: the preconstruction phase, the period between the initial conception of the project and the signing of the contract; and the construction phase, during which the contractor must complete construction subject to the conditions of the contract (Sweis, 2013). Time overruns occur in both phases however, major causes of time overruns usually take place in the constructionphase (Frimpong, Oluwoye and Crawford, 2003).
According to Frimpong, Oluwoye and Crawford (2003) project success can be defined as meeting goals andobjectives as prescribed in the project plan. A successfulproject means that the project has accomplished itstechnical performance, maintained its schedule, andremained within budgetary costs.Project management tools and techniques play animportant role in the effective management of a project.Therefore, a good project management lies in the management tools and techniques used to manage the project. Project management involves managing theresources—workers, machines, money, materials andmethods used. Some projects are effectively and efficiently managed while others are mismanaged, incurringmuch time overruns.The successfulexecution of construction projects and keeping themwithin estimated cost and the prescribed schedulesdepend on a methodology that requires sound engineering judgment (Al-Momani, 2000).Construction industry is necessary in every country because of getting better and also comfortable life which must be provided in order to achieve and become an advanced country within duration of time (Abediet. al. 2011a). The more resources, engineering, labour, materials, equipment, capital, and market exchange are provided from within the national economy, the higher the factor of the extent of self-reliance. The increasing complexity of infrastructure projects and the environment within which they are constructed place greater demand on construction managers to deliver projects on time, within the planned budget and with high quality (Enshassi, Lisk, Sawalhi and Radwan, 2003).
2.3 The Concept of Time Overrun
A construction project is commonly acknowledged as successful when the aim of theproject is achieved in terms of predetermined objectives that are mainly completed the project ontime, within budget and specified quality in accordance with the specifications and tostakeholders’ satisfaction (Abediet. al., 2011a). A vital section specified in the construction contractis the performance period or time of project execution,which is established prior to bidding.The time required to complete construction of publicprojects is frequently greater than the time specified inthe contract. These `overruns’ or time extensions aregranted for many reasons, such as designer changes orerrors, user changes, weather and late deliveries.Current construction projects are complex effortsrequiring the support of the design and constructionprofession. Therefore, a realistic time for project execution will decrease the possibility of disputesbetween state agency and the contractors (Al-Momani, 2000).
Delays happen in most construction project; it could be defined as time overrun either beyond completion date specified in contract or beyond the date that parties agreed upon for delivery of project (Assaf and Ai-Hejji, 2006). Time overrun is having completion times reaching further than what was set out initially (Adam et. al., 2014). Sigh (2010) define ‘time overrun’ as the time difference between the actual and the initially planned (i.e, expected) dates of completion.According to Kaminget. al. (1997) and Trigunarsyah (2004), time overrun is the extension of time beyond planned completion dates usually traceable to contractors. Elinwa and Joshua (2001) defined it as the time lapse between the agreed estimation or completion date and the actual date of completion. Bramble and Callahan (1987) described time overrun as the time during which some part of construction project is completed beyond the project completion date or not performed as planned due to an unanticipated circumstance.
Most construction projects in developing countries are characterized by overruns in time. Time overrun is a very frequent phenomenon and is almost associated with nearly all projects in the construction industry (Sweis, 2013 and Shanmugapriyal and Subramanian, 2013). According to Shanmugapriyal and Subramanian (2013) time overruns has been a major issue in construction projects. The successful execution of construction projects and keeping them within prescribed schedule is very important for effective time performance. The responsibility of time overruns is distributed over several factors. A new type of construction projects has not escaped the overwhelming ghost of overruns (Sweis, 2013). The history of the construction industry worldwide is full of projects that were completed with significant time overrun. The problem of project time overrun is of international concern(Ameh and Osegbo, 2011). The challenge of time and cost overrun in construction projects is not locally situated. It is a global phenomenon that has assumed an international dimension. The domain of its seemingly ravaging effect cut across many countries and continents of the world (Adindu and Ibironke, 2012). In a study by Shanmugapriyal and Subramanian (2013) in India, construction projects are facing a serious issue of time overrun. The unfortunate part is that very few projects get delivered in time. Time overruns have become the hallmark of construction projects. Mbachu and Olaoye (1999) opined that the Nigerian construction industry is bedevilled by projects that are completed much longer than mutually planned. This was buttressed byOdusami and Olusanya (2000) who concluded that most projects executed in the Lagos metropolis experienced an average time overrun of 51% on their planned duration.Al-Momani (2000) conducted a survey on 130 public projects in Jordan and found delays occurred in 106 (82%). Frimpong, Oluwoye, Crawford, (2003) observed that 33(70%) out of 47 projects in Ghana were delayed.Ajanlekoko (1987) found out that on-time completion hardly ever happens in construction industry in Nigeria. Odeyinka and Yusif have shown that seven out of ten projects surveyed in Nigeria had holdup. A filed survey in Saudi Arabia conducted that 70% of projects experienced time overrun and found that 45 out of 76 projects considered were delayed. (Assaf, Al-Hejji, 2006). Chan and Kumaraswamy studied delays in Hong Kong building industry. They underlined that appropriate release of projects within budget and to the level of quality standard specified by the client is an index of victorious project delivery.
Furthermore, the length of the time overrun is also dependent on the type of project undertaken. Maintenance projects generally experience the most severe time overruns (Bordat, et. al., 2004). This may seem counterintuitive as pointed out by Bhargava (2010), maintenance projects are after all fairly standardized and one might then expect them to be less prone to and time overruns. On the contrary, road maintenance projects are frequently associated with unpredictable and unforeseen site conditions that often require the relocation of utilities and redirection of traffic flow which in turn tends to result in significant time overruns (Cited by Adam et. al.2014). Whereas maintenance projects were most problematic in terms of time overruns, Bordatet. al. (2004) found that bridge and resurfacing projects were consistently better with respect to time overruns (on average 94 and 101 day respectively, compared to 153 days for maintenance projects).These delayed projects are further can conclude additional delays and this affects an on-going projects and also new projects which could not be started due to pending projects whose completion date is already elongated(Ashwini and Rahul, 2014).
The responsibility of time overruns is distributed over several factors(Sweis, 2013).There is no particular element in any project solely responsible for time overruns however; the construction phase holds a wider proportion of major troubles. Construction time overruns are integrated parts, none of them can be divided from the other (Sweis, 2013). The problem of time overrun is widespread and severe, only a small number of projects get delivered in time (Sigh, 2010). Sigh (2010) proposed that every infrastructure project has to undergo several stages: from planning of the project, to its approval, to awarding of contract(s), to actual construction/procurement, and so on. Broadly put, a project’s lifecycle has three phases; development, construction, and operation-and-maintenance phase. In the beginning of the development phase, the project sponsoring department prepares estimates of time and cost (funds) needed to complete the project. An expected date of completion is also announced. The actual date of completion is invariably different from the expected date.The time difference is measured in months. A related term used in the paper is the ‘implementation phase’ or ‘implementation period’. It is defined as the duration in which a project is planned to be completed, that is, the duration between the date of approval of the project and its expecteddate of completion. Therefore, for each project we can define percentage time overrun as the ratio of the time overrun and the implementation phase for the project (multiplied by one hundred). Clearly, the time overrun and therefore the percentage time overrun can be positive, zero or even negative.
In a study, Rwakareheand Mfinanga (2014) considered time overrun as the time difference between the actual and the initially planned (expected) dates of completion. The original completion dates for individual projects as well as the actual completion dates were extracted from respective project completion reports. The difference between the two dates is the time overrun and the percentage ratio of this difference to the original contract duration was used to define the time overrun rate.Normally, when the projects are time-overrun, they are either extended or accelerated and therefore, incur additional cost. The normal practices usually allow a percentage of the project cost as a contingency allowance in the contract price and this allowance is usually based on judgment. Although the contract parties agreed upon the extra time and cost associated with delay, in many cases there were problems between the owner and contractor as to whether the contractor was entitled to claim the extra cost. Such situations, usually involved questioning the facts, causal factors and contract interpretation. Therefore, delays in construction projects give rise to displeasure to all the parties involved and the main role of the project manager is to make sure that the projects are completed within the budgeted time and cost. (Murali, Sambasivan, Yau Wen, 2007)
In a study by Ijigahet. al. (2012) on the analysis and prediction of cost and time overrun, Regression method of analysis was adopted, where relationship between variables is determined to be
y=a + bx
Where; y – is a dependent variable, (Time Overrun, %Time Overrun); x – is an independent variable (Project Duration)
The following equation were also used in the analysis
Time overrun = actual project duration – estimated project duration
%time overrun = time overrun x100
Estimated project duration
Total regression analysis reveals the following models;
y = – 0.467 + 0.330x
Where; y = time overrun; x= project duration.
y = 28.292 + 0.057x
Where; y = % time overrun; x = project duration.
Some researchers have identified the connection between delay and time overrun in their studies. Lo, Fung and Tung (2006) define delay as the slowing down of work without stopping construction entirely and that can lead to time overruneither beyond the contract date or beyond the date that the parties have agreed upon for the delivery of the project. In the same vein Sweis (2013) defined delay to mean non-completion of the project within the specified duration agreed on in the contract. Similarly, Ashwini and Rahul (2014) stated the occurrence of delay may concurrently be with other delays and all of them can impact the project completion date.
Generally; Construction delay is considered to be one of the most recurring problems in the construction industry and it has an adverse effect on project success in terms of time, cost, quality, and safety (Sweis, 2013). Time delays have long been regarded a common phenomenon (Adam et. al., 2014). Ashwini and Rahul (2014) also emphasised the high frequency of delay by suggesting that the delay problem in the construction industry is a worldwide phenomenon and is considered to be one of the recurring problems in the construction industry. Delays occur in most construction projects, either simple or complex (Ashwini and Rahul, 2014). Delays are among the challenges faced in the course of executing construction projects (Kikwasi, 2012).
In construction, the word “delay’’ refers to something happening at a later time than planned, expected, specified in a contract or beyond the date that the parties agreed upon for the delivery of a project (Pickavance, 2005). According to Kikwasi (2012) delay as referred in construction is prolonged construction period. Delays in project are those that cause the project completion date to be delayed (Al- Gahtani and Mohan, 2007). In construction, delay can be defined as the extension of time in the completion of project. In short delay means failure to complete project in targeted time(Ashwini and Rahul, 2014). According to Kraiem and Diekmann (1987) not all delays can be attributed to the contractor. Scheduling delays are typically divided into:
a) Excusable delays;
b) Compensable delays; and
c) Non-excusable delays.
The first category refers to delays in which neither the client nor the contractor can be assigned blame, typically a force majeure clause is included in the contract to addresses this. Compensable delays are those where the contractor is owed a compensation for delays caused by an unwarranted course of action taken by the client. This might consist of changes in the scope of the project or change of site conditions that differ from what the client stated. Non-excusable delays refer to delays caused by the actions or lack of action by the contractor and where the client may be subject to compensation from the contractor.
The classification of delays into the aforementioned groups, though useful, does not necessarily offer a complete account of time related complications. Instead, as Arditi and Pattanakitchamroon (2006) points out, there are several different situations in which it becomes difficult to assign the cause of a delay to a specific party. This in turn renders it difficult to enforce legal ramifications in terms of which party should compensate the other. This is particularly palpable in the case of concurrent delays, a type of project delay whereby two or more delays occur simultaneously, either of which would have caused the entire project to exceed the time limit had it occurred by itself (Rubin, 1983)
According to Menesi (2007), delays are classified into three different types:
1. Excusable,
2. Inexcusable, and
3. Concurrent.

Figure 2.1: Types of Delay.
Source: Menesi (2007)
According to Ashwini and Rahul (2014) delays that affect project completion date as agreed on contract are considered as critical delays, while delays that do not affect project completion date are known as non-criticaldelays. An excusable delay is beyond the contractor control that is, delay due to unforeseeable activity beyond the contractors or the sub-contractors control. Excusable delays without compensation are delays caused by neither the client nor the contractor. Non-excusable delays (NEDs) are within contractor control. NEDs are the responsibility of contractor and the client may be entitled to claim the damages.Only excusable delay can be compensable delay. A compensable delay is a delay where the contractor is entitled to a time extension and to additional compensation. Under non-compensable delay the contractor is not entitled to any compensation resulting from the excusable delay
When the same type of delay happens more than one time, either alone or consequently, impact the projects critical activity schedule, a concurrent delay occurs. The concurrent delay can also be classified as:
Table 2.1: Classification of concurrent delay according grant to the contractor
Delays that occur concurrently Entitlement to the contractor
Excusable and Non-excusable Only time extension granted
Excusable with compensation and excusable without compensation Entitled to time extension but not to damages
Two excusable with compensation Entitled to both time extension and damages
Source: Wei(2010)
In addition, Syed, Azhar, Castillo and Kappagantula, (2002) classified delay into:
1. Non-excusable delays,
2. Excusable non- compensable delays,
3. Excusable compensable delays and
4. Concurrent delays.
Non-excusable delays are delays, which the contractor either causes or assumes the risk for. Excusable non-compensable delays are delays caused by factors that are not foreseeable, beyond the contractor’s reasonable control and not attributable to the contractor’s fault or negligence. Compensable excusable delays these are compensable delays are excusable delays, suspensions, or interruptions to all or part of the work caused by an act or failure to act by the owner resulting from owner’s breach of an obligation, stated or implied, in the contract. Concurrent delays occur when both owner and the contractor are responsible for the delay.
In addition, Ahmed et. al. (2003) found that in most of the cases there is no excuse for the delay when it is caused by the contractor, while this delay could be excusable and compensable when the responsibility is on the owner or the consultant. However, when the delay is the responsibility of the government, it’s always excusable and compensable.

2.4 Sources of Time Overrun
There are various causes due to which project suffers from these time overruns. As the project is running on many number of factors and participants, these all are having individual causes (Ashwini and Rahul 2014). But the important participants like owner, contractor, and consultant have more influence on project performance (Ashwini and Rahul 2014). The most significant group that causes delay is contractor related, followed by client-related and consultant related (Wei, 2010). Likewise Ogunlana, Promkuntong, and Jearkjirm’s (1996) study in Thailand and Kaminget. al.’s (1997) study in Indonesia found that the blame for most project delays were laid on the contractor. Abd-Majid and McCaffer (1998) found that 50% of the delays to construction projects are those for which the contractors were responsible.There are however, time overrun caused by events beyond the control of either the owner or the contractor. Such delays may rise as a result of force majeure, exceptionally inclement weather, civil commotion, industrial unrest, just to mention but a few(Ameh and Osegbo, 2011).Shanmugapriya and Subramanian (2013) also identified contractor, consultant and owner as the sources of time overrun in construction projects. Chang (2002) categorized the reasons for time overruns in engineering design projects as follows: those within the owner’s control (for which the owner is responsible); those within the consultant’s control (for which the consultant is responsible).
According to Al-Najjar, (2008), it was observed that contractors and owners agreed that ‘’shortage of materials’’ is one of the delay causing factors and this is contradicting with consultant’s view point another example was that consultants considered ‘’major dispute’’ as a root cause of projects delay while the matter is vice versa for both contractors and owners. The best interpretation for such differences involved in the findings will be best interpreted based on the nature of work of each party. Each party deals with delay process in order to avoid delay responsibility. From the contractor’s point of view they always consider shortage of materials as the main factor, while owners are usually fluctuated according to their interest and sometimes highly agreed with contractors and slightly with consultants, and sometimes vice versa.Furthermore, Alaghbari,Razali, Salim, and Ernawati (2007) examined the major factors of time overrun in Malaysian construction projects to be factors due to contractors, factors due to consultants, factors due to owners and finally external factors. Hence the sources of time overrun can be grouped into:
a) Client or owner;
b) Contractor;
c) Consultant or designer; and
d) External factors
Hence the factors influencing time overrun from these participants are discussed which will helpful to improve the project delivery in terms of time as well as cost efficiency.

2.5 Factors Influencing Time Overrun
Jaskowski and Biruk (2011) pointed out that project activities’ durations are directly affected by different risk factors independently. Every activity within the project has its own time and cost estimates with different processes differentiating the type of work undertaken to accomplish these activities. All differ and affected by different risk factors that might have a major impact on one and slightly affect the other. According to Ashwini and Rahul (2014) all construction projects undergo several phases that are shown in figure 2.2. The under development period is before the projects is put forward for approval. In development period the projects are put forward and headed towards for approval of it. During construction period project comes to execution of work. Operating/performance period shows the time span of operation and under maintenance period project is continued through maintenance.

Figure 2.2: Project Phases

Source: Ashwini and Rahul (2014)
In time overrun project experiences delays in construction period where different gaps occurred between the actual progress on site work and scheduled work. Hence, projects are failed to complete in construction period as per contract and this failure to achieve targeted time, budgetedcost and specified quality results in various negative effects(Ashwini and Rahul, 2014). This was buttressed by Sweis (2013) who opined that the construction phase holds wider proportion of major troubles. Conversely, Chalabi and Camp (1984) found that time overruns of construction projects occur entirely in the very early stages of the project i.e. during the planning stages of project development.Aibinu and Jagboro (2002) opined that it is not uncommon for delays to happen during the design phase.
The causes and effects of time overrun factors in construction industry vary from country to country due to environmental, topographical and technological constraints (Sweis, 2013). Kikwasi (2012) also buttressed this by proposing that major causes of time overrun seem to differ significantly from one country to another. In anticipation of the effect of globalization and the technological difference between developing and developed countries, it is necessary to identify the actual reasons of delay in order to reduce the impact of delay in any construction project (Shebobet. al., 2012).Gündüz, Nielsen, and Özdemir (2013) stated that in the construction industry, contractors tend to maximize their profit to increase market share. To achieve this aim, it is crucial for contractors to carefully identify the factors that affect the success of a project and estimate their impacts before the bidding stage
In Pakistan Haseeb, Xinhai-Lu, Bibi, Maloof-ud-Dyian, and Rabbani (2011) point out that the most common factors of time overrun are natural disaster like flood and earthquake. The study also acknowledged others which are: financial and payment problems, improper planning, poor site management, insufficient experience, and shortage of materials and equipment. Furthermore, Algharbiet. al. (2007) examined the factors behind time overrun in construction projects in Malaysia. Results showed that the financial issue is the dominating factor among other factors that cause the delay of construction project in Malaysia. Coordination problems came next after the financial factor followed by materials problems. In Tanzania, Kikwasi (2012) identified the causes of time overrun to included design changes, delays in payment to contractors, information delays, funding problems, poor project management, compensation issues and disagreement on the valuation of work done.
In the Middle East several similar studies were carried out. Major causes of delay in Saudi Arabia were slow preparation and approval of shop drawings (Assafet. al., 1995). In Lebanon, however, the owners concerns with regard to financial issues ranked highest among the delay causes (Mezher and Tawil, 1998). Additionally, Al-Moumani (2000) identified poor design and change orders as the leading causes of delay in Jordan. While Koushkiet. al. (2005) regarded changing orders and owner financial concerns as the top factors affecting delays in the Kuwaiti construction industry. Also, Faridi and Al Sayegh (2006) recognized that slow preparation of drawing was a major factor affecting delay in the United Arab Emirates construction sector
In order to mitigate the occurrence of time overruns managers must first be able to identify the lead causes behind time overruns as this constitutes an essential step in finding a suitable solution (Adam et. al., 2014). Al-Najjar (2008) opined that the causes of time overruns can be divided into three categories:
1. Those over which neither party to the contract has any control;
2. Those over which the owner (or his/her representative) has control;
3. Those over which the contractor (or any subcontractor) has control.
In Indonesia, according to Kaminget. al. (1997) factors influencing time overruns are environment restriction, experience of project location, inaccurate prediction of equipment production rate, equipment availability, lack of experience of local regulations, weather conditions, locational restriction of the project, inadequate level of planning and material unavailability. Alwi and Hampson (2002) identified and grouped factors influencing time overruns as
1. Owner: poor finance and late payments of completed work, owner interference, slow decision-making by owners, unrealistic imposed contract duration
2. Contractor: problems from subcontractors, poor site management, poor construction methods, improper planning,mistakes during construction, inadequate contractor experience.
3. Consultant: poor contract management, late preparation and approval of drawings, poor quality assurance and control, waiting for approval of tests and inspections.
4. Material: poor quality of material, shortage in material.
5. Labour and equipment: poor labour supply, poor labour productivity, equipment unavailability and failure.
6. Contract: change orders, mistakes and discrepancies in contract documents.
7. Contractual relationships: major disputes and negotiations, inappropriate overall organizational structure linking, lack of communication between the parties.
8. External factors: weather condition, regulatory changes and Building Code, problems with neighbours, unforeseen ground conditions
Chan and Kumaraswamy (2002), Alwiet. al. (2002), Assafand Al-Hejji(2006), Odeh and Battaineh (2002) and Alghbariet. al. (2007) Classified factors that cause time overrun into eight groups and they are;
1. Owner,
2. Contractor
3. Consultant
4. Material,
5. Labour and
6. Equipment
7. Contract
8. Contractual relationships and External factors
A quantitative analysis on construction delays in Jordan has been carried out by Al-Momani (2000). Results indicated that the main causes of delay in construction of public projects were related to designers, user changes, weather, site conditions, late deliveries, economic conditions and increase in quantity. Similarly, Abdalla and Battaineh(2002) conducted a survey aimed to identify major causes of delays in construction projects with traditional types of contracts from the viewpoint of construction contractors and consultants. Results of the survey had shown agreement among contractors and consultants that owner interference, inadequate contractor experience, financing and payments, labour productivity, slow decision making, improper planning, and subcontractors were among the top ten most important factors.Pathiranage and Hawaltura (2010) noted that factors causing time overrun include financial problems of the owner as well as the contractor, poor site management by the contractor, poor weather condition, contract modification, incomplete documents, slowness in making decisions, shortage of site labour and material, lack of sub-contractor’s skill or poor skills, construction mistakes, defective works, and poor site condition. In the same vein, Jeykanthan and Jayawardena (2012) identified significant factors causing time overrun to include inadequate feasibility studies, errors and omissions in detail designs, improperly harmonized procurement documents, shortcomings in contract document, stakeholder identification and management issues, variation and scope changes, land acquisition and resettlement and extreme weather.
According to the response by contractors, the chief causes for delays were due to postponements in design information, lengthy duration for approving drawings and inadequate site management. Conversely, consultants attributed delays to primarily unforeseen ground conditions, inadequate contractor experience and poor site management and supervision (Cited by Adam et. al., 2014). The project owners may be responsible for the time overrun when delays, suspensions or interruptions to all or part of the work are caused by an act or failure to act by the owner resulting from breaches of owner’s obligations, stated or implied in the contract. These include failure of the owner or his representative (consultants) to furnish the contractor with relevant information, details etc. for which the contractor has specifically requestedin writing. Rowlinson (1988) referring to the finding of Bromilow (1974) says that project owners were responsible for delays in issuing approvals, signing contracts and allowing site access. The finding also indicated that owners were responsible for the largest proportions of variations, all of which have time and cost implications.Many factors related to time overruns vary along with types of project, location, size and scope of project(Shanmugapriya and Subramanian, 2013). In a research conducted by Dolage and Rathnamali (2013) delay in progress payment by clients, rainy weather, poor liquidity of the contractor and inaccurate planning and scheduling of projects, unavailability of experienced technical staff, excessive work in hand of the contractors, poor liquidity of contractors, shortage of labourers, delay in approving extra work and variation, poor site management and supervision of contractors and ineffective time management of contractors are identified by clients, consultants and contractors as the most significant factors causing time overrun. Ramabathan, Potty and Idrus (2011) stated that high demand on the resources such as labour, material and equipment may cause scarce, and this will hamper the project execution. If this situation prolonged and left unchecked, it may affect the project progress. Ramabathanet. al. (2011) concluded that mismanagement of the project by contractor, consultant and owner will lead to time overrun. Mahamid (2011) mentioned that major causes of time overrun are poor communication between parties, resource management and delay in commencement. Al-Najjar (2008) opined that the predominant factors influencing time overruns/delays are design changes, poor labour productivity, inadequate planning and resource shortages.
Aiyetan, Smallwood and Shakantu (2008) point out that the three most significant factors that adversely impact construction project delivery time performance are: quality of management during construction; quality of management during design, and design coordination.Aibinu and Jagboro (2006) identified contractors’ financial difficulties, the project owners’ cash flow problems, incomplete drawings, subcontractors’ in-competency, equipment breakdown, late delivery of materials, planning problems, price escalation and subcontractor’s financial problems, in that order as leading causes of project time overruns. Ameh and Osegbo (2011) established that among the various factors that causes time overrun, inadequate fund for the project, inadequate planning of project before take-off, inadequate tools and equipment, delay in delivery of materials, subcontractors’ in-competency and design changes during project execution top the lists. Brief reasons for time overruns as reported by various project implementing agencies are delay in land acquisition, delay in equipment erection, inadequate mobilization by the contractor, delay in forest clearance, fund constraints, change in scope of work, cancellation of tender, law and order problem, delay in supply of equipment, slow progress of civil work, escalation in cost (Ashwini and Rahul 2014). Rwakareheand Mfinanga (2014) also identified delay as factor influencing time overrun. According to Ashwini and Rahul (2014) for owner the causes which affect the project are like, changes in plan by owner during construction, less capability of understanding technical terms. Also from the finance point of view, if owner delays in payment of completed work it is going to affect the further work of project. Contractor’s improper planning and scheduling have more influence on project duration, as well as lack of experience will affect the ability of decision making which will result in rework and financing problems. Consultant’s improper drawings, late revising the specification, less coordination with contractor also conclude in project time overrun.Aiyetanet. al. (2008) point out that the three most significant factors that adversely impact construction project delivery time performance are: quality of management during construction; quality of management during design, and design coordination.
While researching the causes of time overrun Sweis (2013) showed a consensus of opinion among the sample members that poor qualifications of consultants, engineers and staff as well as poor planning and scheduling served as main factors contributing to public projects time overrun. Shanmugapriya and Subramanian (2013) identified design changes, poor labour productivity, lack of adequate planning, shortage of materials and inaccuracy of material estimates as the five major causes of time overruns in India.Koushkiet. al., (2005) identified that the three main causes of time overruns are changing orders, owner’s financial constraints and owner’s lack of experience. In a study by Alaghbariet. al., (2007) it is identified that the financial factor is the most influencing factor in causing delay in Malaysian construction projects.
A common manifestation of poor planning is the occurrence of change orders. It offers an indication that events did not pan out as originally intended and tends to lead to both longer completion times as well as increased cost due to the purchase of new materials(Adam et. al., 2014).According to Koushkiet. al., (2005) the three main causes of time overruns are changing orders, owner’s financial constraints and owner’s lack of experience.Doloi,Anil and Lyer (2012) identified the causes of time overrun to include lack of commitment, inefficient site management; poor coordination in site, improper planning, lack of clarity in scope of project, lack of communication, slow decision from owner, poor labour productivity, architects reluctance for change and rework due to mistakes in construction.
Though some factors are more frequently mentioned than others, this does not necessarily imply that they are more influential in determining the scale of the time overruns. Indeed, the frequency by which a particular cause is mentioned may instead offer an indication of it being easily observable as opposed to having a greater impact(Adam et. al., 2014).Shanmugapriya and Subramanian (2013) noted that despite the importance and the significance of the construction sector the owners, consultants, and contractors do not give its importance to evaluate the time overruns at the end of project.

2.6 Effects of Time Overrun
Ashwini and Rahul (2014) considered time overruns to always contribute as expensive to all parties and has adverse effects on project success in terms of time, cost and quality. Haseebet. al. (2011) identifies effects of time overrun in Pakistan construction industry as clash, claims, total desertion and slowing down the growth of the construction sector. In a study on time overrun by Kikwasi (2012) results indicate highly ranked effects as cost overrun, negative social impact, idling resources and disputes. These results are more less the same as those obtained by and Sambasivan and Soon (2008) in Malaysian construction industry. On the other hand, medium ranked effects include: arbitration, delaying by the client to return the loans and poor quality of work due to hurry.
Time overrun affects the project owners, contractors and other project participants. Project owners may be affected through lost benefits that could have accrued from the completed facility, while contractors may have to spend more on labour and plant, pay penalties as per the contract or even lose other profitable contracts because resources for the next job are tied up on delayed projects. The contractor on the other hand bears the risk associated with time overrun on matters related to low labour productivity, inadequate scheduling or mismanagement, construction mistakes, weather, equipment breakdowns, staffing problems, etc. (Ameh and Osegbo, 2011). In a study on time overrun Shanmugapriya and Subramanian (2013) suggested that time overruns reduce the productivity of available economic resources, edge the development potential and diminish the effectiveness of the economy.Time overruns have long been regarded a common phenomenon, due to the magnitude and frequency of these overruns; they have come to pose a significant financial risk to both clients and contractors (Adam et. al.2014). Time overruns reduce the efficiency of available economic resources, limit the growth potential and reduce competitiveness of the economy (Singh, 2010).
According to Saleh, Abdelnaser and Abdul (2009), construction time overrun is a critical function in construction project and also one of the biggest problems construction firms face in Libya. In this study, the items of contractor’s factors that cause delay and gave ranking based on the mean value criteria. And in further analysis they identified the impact of time overrun in construction projects i.e. loss of interest by stakeholder, blacklist by authorities, waste of money and time and declination of reputation. Mohamad(2010) studies the factors and effects of time overrun in government construction project. Research indicates the effects of time overrun to be cost overrun, rescheduling and rearrangement, litigation, disputes and arbitration.

2.7 Mitigating Time Overrun
In order to mitigate the risk of time delays occurring, a number of contractual schemes can be put in place such as the use of liquidated damages. It is not uncommon for a provision to be included in the contract stating that punitive damages must be paid by the contractor to the client in the event of a time delay for which the contractor is responsible (Adam et. al., 2014). In general, such delays do not necessarily result in liquidated damages (Bordat, et. al., 2004).
Despite this being the case, it may not be entirely feasible to eliminate change orders and rework altogether for as Bordat and Sinha (2004) pointed out, few construction projects are exempt from the advent of unforeseen circumstances and projects are therefore rarely completed without changes from the owner. Instead, efforts should be taken to minimize the frequency by which they occur.
According to Ameh and Osegbo (2011), the following should be ensure so as to mitigate time overrun:
• Adequate funding guarantees reasonable cash flow while good planning ensures uninterrupted progress of work and these are basic ingredients for the realisation of key objectives of any project. The project owner and project manager should keep their eyes on these key factors during project execution as these factors could result in reasonable time overrun on projects.
• There should be effective funding of project by project owners to avoid unnecessary time overrun with its attendant effect on cost. To guarantee achievement of the construction programme, the project owner could engage the service of a project manager to manage the project from the design stage through tendering to completion.
• Contractors and subcontractors should provide adequate and functional working tools/equipment for their workers to enable timely completion of projects. Equally, in every medium to large scale projects, the project team composition should include a dedicated staff trained on materials management and store keeping to ensure effective and efficient management of construction materials. The contractor or sub-contractor could establish a maintenance department that is managed by experienced technician on construction sites to ensure prompt repair of any damaged tools/equipment.
• The project manager should ensure that both nominated and domestic sub-contractors on any project have the requisite experience and work plan to meet the requirements of the main contractor. Pre-qualification of these sub-contractors would ensure that the ones engaged have sufficient experience, proficiency and capacity to deliver not only quality work but on time. The project owner (or project manager) must ensure completion of all design documentation with any associated value engineering analysis and buildability reports before tendering, so that design changes during project execution is minimised.
• The project manager should ensure the submission of method statements by the contractors in the course of bidding for any construction project. This to a large extent would determine the contractor’s understanding of the work and the application of good construction method and technology that will guarantee prompt realisation of project objectives.
• Government should encourage skill acquisition especially among the teaming unemployed youth through development of technical colleges for training of workers in various construction trades. Good skills within and among the workers would exert reasonable quantum of positive influence on labour productivity more especially when backed by adequate supervision of operatives. Contractors and sub-contractors should as a matter of policy train and retrain skilled and semi-skilled workers to enhance their skills which will eventually improve on the labour productivity.
• Contractors and subcontractors should ensure adequate training and supervision of the operatives on construction sites as it would improve on the quality of output as well as minimize the chances of doing wrong work or even application of wrong construction method by the workers. Equally, supervisors should be well grounded in any aspect of work they are in charge as it would not only earn them respect but add value to quality of the completed work.
Ijigahet. al.(2012) suggest that to reduce time overrun there is also the need to incorporate into tender the expected time variation as this will address time overrun of construction projects hence avert the incidence of project abandonment resulting from time overrun of construction projects. According to Sweis (2013),one of the major factors causing construction projects time overrun was governmental delays and design changes, due to this, systematic steps must be taken, and can be illustrated by reforms and change of regulations required to accelerate the approval process of the government. Moreover more attention should be given during the design phase to minimize the probability of change orders.
Kikwasi (2012) opined that adequate construction budget, timely issuing of information, finalization of design and project management skills should be the main focus of the parties in project procurement process. In Nigeria, Aibinu and jagboro (2002) suggest that acceleration of site activities coupled with improved owner’s project management procedures and inclusion of an appropriate contingency allowance in the pre contract estimate were recommended as a means of minimizing the adverse effects of construction delays in Nigeria.
According to Shanmugapriya and Subramanian (2013) contractors are to be attentive about construction materials and prices, so they are advised to purchase the construction materials at the commencement of work. Time schedule for material delivery to the site and usage of materials in the site must be prepared in order to avoid shortage or lack of materials. Qualified staff with appropriate experience must be appointed so as to avoid any mistakes that may lead to rework of activities, and finally time overruns. Site planning and management, administrative and technical staff should be assigned as soon as project is awarded to make arrangements to achieve completion within specified time with the required quality and estimated cost. Contractors are recommended to have enough cash before beginning in any project to avoid the financial problems. Owners are recommended to revise the bid documents such as specifications. This is because any discrepancy in bid documents will lead to disputes between projects parties and so delay may occur in the projects. Progress payment must be paid to the contractors on time because it impairs the contractor’s ability to finance the work. Owners are also recommended to have competent Project Manager who is capable to manage the different stages of any project and to follow the performance percentages, and also able to compare the actual performance with the planned one. Owners should minimize change orders as possible as in order to avoid any time overruns. Consultants are recommended to review and approve design documents, shop drawings, and payments of contractor to avoid any delay or cost overruns at the project. It is also advised for consultant to have high qualification and knowledge to give suitable instruction in a suitable time and to be able to answer any question stated by contractor to avoid overruns. Consultants should be flexible in evaluating contractor works. They should consider compromising between cost and high quality.

2.8 Summary
In this chapter various literature in connection with the research objectives were reviewed and the concept of time overrun was discussed, sources of time overrun were identified, factors influencing time overrun were identified and discussed, the effects of time overrun and how to mitigate the occurrence of time overrun in construction projects were also identified and discussed. This helped to identified myriad and interplaying factors with their debilitating effects from different project participants in a construction project leading to time overrun. This has provided information and basis on which the research questionnaires can be made for data collection. The next chapter presents the research methodology.

3. RESEARCH METHODOLOGY
3.1 Introduction
This chapter discussed the research methodology as well as the research design used in carrying out the study. The aim and objectives of this study was pursued by collection and analysis of suitable data to achieve them. Primary data and archival data were collected and analysed using statistical methods of percentages, relative significant index as well as regression analysis. It also highlighted the presentation tool used for the analysis which is the Statistical Package for Social Sciences (SPSS)

3.2 Research Design
“Research design” refers to the plan or organization of scientific investigation, designing of a research study involves the development of a plan or strategy that will guide the collection and analysis of data(Poilt and Hungler, 1985). This research consists of fivephases; the first one is the proposal for identifying and defining the problems and establishment of the objectives of the study and development of research plan. The second phase of the research includes literature review. The third phase of the research includes the questionnaire design. The fourth phase of the research was questionnaire distribution to construction professionals and collection of archival data of executed projects from quantity surveying firms in the study area. The questionnaire was used to collect the required data in order to achieve the research objectives. The fifthphase of the research focused on data analysis and discussion. Statistical Package for the Social Sciences, (SPSS) was used to perform the required analysis. The last phase of the research includes the conclusions and recommendations.

3.3 Study Population
The study area adopted for this research was Lagos State. The study population comprised architects, quantity surveyors, engineers and builders in the study area. There are 1109 different professionals in the construction industry selected from the list of their respective professional bodies and with respect to those that are financial members of Nigerian Institute of Quantity Surveyor (NIQS), Lagos State Chapter, there are 57 registered quantity surveying firms in the study area according to the statistics obtained from the website of the Nigerian Institute of Quantity Surveyor (NIQS), Lagos State Chapter (2015).

3.4 Sampling Frame
The sampling frame included 57 (NIQS, 2015) registered quantity surveying firms in the study area and the total population of 1109 professionals in the study area this comprise Architects, Quantity Surveyors, Engineers,and Builders. Details are shown in table 3.1 below

3.5 Sample Size
For primary data collection, the target population include those who have participated actively in project executions and are still active. This is to ensure that adequate data are collected. From the sample frame of 1109 construction professionals in Lagos State, the sample size was calculated using Cochran formula. It gives a sample size of 138 with sample ratio of 12.44%.
Cochran formula: n = t2×s2
d2
Where: n=sample size;t= t value for the acceptable margin error(t=1.96); s= estimate of variance in the population distribution; d= acceptable margin of error (0.05).

Table 3.2 Sample Size of Professionals

The sample size is distributed among the professionals to be 43 Quantity Surveyors, 31Architects, 37 Engineers, and 27 Builders.
Archival data of 43 executed projects were randomly collected from quantity surveying firms due to time, financial constraints and the busy schedule of the firms. The sample size is considered adequate going by the recommendation of Alston and Bowles (2003) that a required minimum sample size of 30 is regarded sufficiently large to provide an effective statistical analysis.

3.6 Method of Data Collection
This study made use of primary data and archival data. Primary data was collected through structured copies of questionnaire administered on the major construction professionals in Lagos state. Respondents were requested to answer the questions by completing the questionnaire supplied. The respondents were selected using random sampling method.
The questionnaire contained two sections A and B. Section A asked questions pertaining to respondents’ personal details whereas Section B elicited information on the research objectives. The questionnaire was prepared in Likert type scale of one to five to sample the opinion of the respondents to indicate their level of assessment concerning the concepts measured.
The questionnaire was designed to include the variables that were identified in the literature review and evaluated by asking the respondents to rate based on a scale chosen, the factors represent their opinion on their level of significance and frequency. The research involved quantitative data; hence the questions asked required qualitative answers which required rating using an interval scale. For example:
a) Highly significant/frequent 5
b) Significant/frequent 4
c) Fairly Significant/frequent 3
d) Less Significant/frequent 2
e) Not significant/frequent 1
This shows a rating of 5 to 1.
The level of significance and frequency of the factors were identified by the respondents rating them on a scale
The administration of the questionnaires was carried out manually. Visits were made to the various firms by the researcher and the questionnaires administered. Subsequent visits were made, to ensure successful completion and return.
Archival data of executed projects were collected from registered quantity surveying firms in the study area. Information like the projects classification, planned and actual completion time, year of execution and planned and actual completion cost of each project were collected.

3.7 Method of Data Analysis
For the purpose of this research work data analysis was carried out using descriptive method of analysis. The method adopted to describe the collected data for the research work were in form of frequency, percentage, mean score and ranking in order to reveal the sources of time overrun, factors influencing time overrun, relationship between factors influencing time overrun and time overrun of construction projects and effects of time overrun on completion cost of construction projects. The primary data were analysed using measures of central tendency such as means, percentiles and relative important index for the purpose of this study. The following were used to arrive at a proper conclusion of the analysis. The descriptive methods include:
a) Percentile: It involves the proportion of response to a particular option by a respondent to the total number of respondents expressed in percentages. The option having the largest number of response was considered as representing the majority upon which the final decision was based.
The percentage was calculated using the mathematical formula:
Percentage =∑F x 100%
∑FX

Where “∑” is the sum and “F” is the Frequency.Also,

b) Relative importance index: This was adopted to rank the relative significance of the factors influencing time overrun according to the opinion of the respondents with the use of five-point Likert scale range 1-5
Relative Importance Index (RII) = ∑Wi xi(0≤ index ≥ 1)
A x N
Where W= weighting given to each factor by the respondents ranging from 1-5
x= frequency of ith response given
A= Highest weight (i.e. 5 in this case) and
N= Total number of respondents.
c) Regression Analysis: This is a statistical process for estimating the relationships among variables. It analysis the degree of the relationship between a dependent variable and one or more independent variable. The dependent variable is cost overrun, and independent variable is time overrun. Regression analysis helps to understand how the typical value of the dependent variable changes when the independent variable is varied. Different regression models were analysed and the one with the highest predictive power was selected.

4. DATA PRESENTATION, ANALYSIS, AND DISCUSSION OF FINDINGS
4.1 Introduction
This chapter contains the analysis of data received through the administered questionnaires and secondary data received and presentation of results. It also explains the method of measurement used and the type of analysis carried out. All the data were presented using tables for clarification and better interpretation. From the analysis different conclusions were made in connection with the aim and objectives of this study. The aim of this is to use the empirical data to achieve the objectives of the study.

4.2 Presentation of Descriptive Data and Demographic analysis
The descriptive data and demographic status of the respondents were assessed to confirm the reliability of the data collected. The descriptive and the demographic status include response rate, type of firm, designation of respondent, highest academic qualification, professional affiliation, years of experience of respondent.

4.2.1 Response Rate
The response rate is shown in table 4.1
Table 4.1 Rate of Questionnaire Response

Table 4.1 showed that a total of 113 properly completed questionnaires representing a response rate of 81.9% percent of the 138 copies distributed were returned for analysis and provided data for the study. The questionnaires were returned thus; Quantity Surveyor (36), Builders (21), Engineer (32), Architect (24). The coverage area of this distribution was Lagos.

4.2.2 Nature of Organization
The nature of the organizations are shown in table 4.2
Table 4.2 Nature of Organisation

Table 4.2 revealed the type of firms where the questionnaires were administered to and from which the data were gathered. The table showed that respondents from consulting firms has the highest frequency of 51 with 45.1%, followed by a frequency of 34 from contracting firms with 30.1%, then a frequency of 28 from Government establishment with 24.8%. This confirmed that the data for this study has been obtained from major players in the construction industry.

4.2.3 Profession of Respondents
The profession of the respondents is shown in table 4.3 below
Table 4.3 Profession of Respondents
Organization Frequency Percentage response (%)
Quantity Surveyor 36 31.9
Builder 21 18.6
Engineer 32 28.3
Architect 24 21.2
Total 113 100

Table 4.3 revealed the professionals to whom the questionnaires were administered to and from whom the data were gathered. The table showed that Quantity Surveyor has the highest frequency of 36 with 31.9%, followed by a frequency of 32 for Engineer with 28.3%, then a frequency of 24 for Architect with 21.2% and Builders with a frequency of 21 with 18.6%. This shows that the information as regards the study had been obtained from relevant professionals in the construction industry who are involved in the time-cost factors of construction projects.

4.2.4 Respondents’ Highest Academic Qualification
The educational qualification of respondents is shown in table 4.4
Table 4.4 Respondents’ Highest Academic Qualification
Academic Qualification Frequency Percentage response (%)
HND 28 24.8
PGD 4 3.5
B.Sc/B.Tech 33 29.2
M.Sc 48 42.5
Total 113 100

From the table, HND holders were 24.8% of the sample, PGD holders were 3.5%, and B.Sc./B.Tech holders were 29.2% while M.Sc. holders were 42.5%. This showed that the respondents had adequate qualification for involvement in the construction industry and in this research.

4.2.5 Respondents’ Professional Qualification
The professional qualification of respondents is presented in table 4.5
Table 4.5 Respondents’ Professional Qualification

About 34.5% of the respondents were probationer or graduate members of their respective professional institutes. Also, corporate members were represented by 56.6% while the remaining 8.9% has fellow membership. This further assessed the genuineness and creditability of respondents.

4.2.6 Respondents’ Years of Experience
The respondents’ year of experience is shown in table 4.6 below
Table 4.6 Respondents’ Years of Professional Experience

About 23.9% of respondents had between 6-10 years of experience in the construction industry, while 13.3% and 19.5% had 11-15 and 1-5 years of experience respectively. 6.2% had between 21-25 years of experience. Furthermore, 16.8% had above 25 years of experience and 20.4% had between 16-20 years of experience. The average year of experience of the respondents was 14.02. This established that the information as regards this study has been obtained from highly experienced and qualified professionals who had been in the industry for quite a period of time and have enough experience to provide reliable response for this research.

4.2.7 Number of Projects handled by Respondents since Commencement of Practice
The number of projects handled by respondents since commencement of practice is shown in Table 4.7 below
Table 4.7 Number of Projects handled by Respondents since Commencement of Practice

About 13.3% of respondents had executed between 1-5 projects while 26.5% and 4.4% had executed in the range of 6-10 and 11-15 projects respectively. Furthermore, 13.3% had executed between 16-20 projects. 15.0% had executed between above 30 projects. 18.6% and 8.9% had executed between 21-25 and 26-30 projects respectively. The average number of projects executed by respondents was 17.05. This further confirmed that respondents have enough experience in providing meaningful data needed for this research.

4.3 Data Presentation, Analysis and Discussion of Findings in Respect of the Stated
Objectives of the Study
4.3.1 Objective 1: Identification and assessment of the sources and causes of time overrun on construction projects in Lagos State.
Respondents were asked to rate the frequency of sources of time overrun of construction projects. The responses are shown in table 4.8 below.

Table 4.8 Relative Importance Index (RII) showing the ranking of the Frequency of Sources of Time Overrun
Sources RII Rank
Client 0.82 1
Contractor 0.73 2
Consultant 0.66 3
External factors 0.48 4

Here, table 4.8 revealed the different sources of time overrun in construction projects with the aim of determining the most frequent source. It is shown that from table 4.8, four (4) different sources of time overrun were identified so as to know the most frequent source of time overrun. All the factors showed high frequency of occurrence except one ranged (0.82 – 0.48). From the analysis above, it revealed that the most frequent source of time overrun in construction projects is the Client (RII= 0.82), Contractor ranked next (RII= 0.73), Consultant ranked third (RII= 0.66). External factor ranked last (RII= 0.48). This analysis showed that the listed sources except external factors ranked above average which depicts that they have high frequency of occurrence.
NOTE/KEY:
N: Number of respondents
RII = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of respondents rating an attribute from 1 – 5
Respondents were asked to rate the significance of impact of sources of time overrun of construction projects. The responses are shown in table 4.7 below

Table 4.9 Relative Importance Index (RII) showing the ranking of the Significance of Impact of Sources of Time Overrun

Here, table 4.9 revealed the different sources of time overrun in construction projects with the aim of determining the most significant source. It is shown that from table 4.9, four (4) different sources of time overrun were identified so as to know the most significant source of time overrun. All the factors showed high significant impact ranged (0.74 – 0.50). From the analysis above, it revealed that the source of time overrun in construction projects with the most significant impact is the Client (RII= 0.74), Consultant ranked next (RII= 0.67), Contractor ranked third (RII= 0.62). External factor ranked last (RII= 0.50). This analysis showed that all the listed sources ranked above average which depicts that they all have high significance of impact.
NOTE/KEY:
N: Number of respondents
RII = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of
respondents rating an attribute from 1 – 5.

4.3.2 Objective 2: Identification and assessment of the factors influencing time overrun on construction projects in Lagos State.
Respondents were asked to rate the frequency of client-related factors influencing time overrun of construction projects. The responses are shown in table 4.10 below

Table 4.10 Relative Importance Index (RII) showing the ranking of the Frequency of the client-related factors influencing time overrun on construction projects

Unrealistic contract durations and initial requirement 0.64 5
Here, table 4.10 revealed the different client-related factors influencing time overrun in construction projects with the aim of determining the most frequent factors. It is shown that from table 4.10, five (5) different client-related factors influencing time overrun were identified so as to know the most frequent client-related factor. All the factors showed high frequency of occurrence ranged (0.80 – 0.64). From the analysis above, it revealed that the most frequent client-related factor influencing time overrun in construction projects is Owner’s interference (RII= 0.80), delay in payment ranked next (RII= 0.71), Owner initiated variation ranked third (RII= 0.68), suspension of work ranked fourth (RII=0.67). Unrealistic contract durations and initial requirement ranked last (RII= 0.64). This analysis showed that all the listed factors ranked above average which depicts that they all have high frequency of occurrence.
NOTE/KEY:
N: Number of respondents
RII = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of respondents rating an attribute from 1 – 5
Respondents were asked to rate the significance of impact of client-related factors influencing time overrun of construction projects. The responses are shown in table 4.11 below

Table 4.11 Relative Importance Index (RII) showing the ranking of the Significance of impact of Client-related factors influencing time overrun on construction projects

Here, table 4.11 revealed the different client-related factors influencing time overrun in construction projects with the aim of determining the factor with the most significant impact. It is shown that from table 4.11, five (5) different client-related factors influencing time overrun were identified so as to know the most significant client-related factor. All the factors showed high significant impact ranged (0.83 – 0.74).From the analysis above, it revealed that the most significant client-related factor influencing time overrun in construction projects is Owner’s interference (RII= 0.83), suspension of work ranked next (RII= 0.80), Owner initiated variation and delay in payment ranked next (RII= 0.77), Unrealistic contract durations and initial requirement ranked last (RII= 0.74). This analysis showed that all the listed factors ranked above average which depicts that they all have high significant impact.
NOTE/KEY:
N: Number of respondents
RSI = Relative Importance Index. RII = TWV
5N
TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of
respondents rating an attribute from 1 – 5.

Respondents were asked to rate the frequency of contractor-related factors influencing time overrun of construction projects. The responses are shown in table 4.12 below

Table 4.12 Relative Importance Index (RII) showing the ranking of the Frequency of Contractor-related factors influencing time overrun on construction project

Here, table 4.12 revealed the different contractor-related factors influencing time overrun in construction projects with the aim of determining the most frequent factor. It is shown that from table 4.12, thirteen (13) different contractor-related factors influencing time overrun were identified so as to know the most frequent contractor-related factor. All the factors showed high frequency of occurrence ranged (0.66 – 0.57). From the analysis above, it revealed that the most frequent client-related factor influencing time overrun in construction projects is insufficient number of staff (RII= 0.66), contractor’s experience ranked next (RII= 0.61), low productivity of labour, poor site management, mistakes during construction, inappropriate construction methods, lack of commitment by contractor to consultant instruction, and poor material handling site ranked third (RII= 0.60), equipment and tool shortage on site, slow information flow between project team members, inadequate construction planning, rework of bad quality performance ranked fourth (RII= 0.58). Shortage of construction materials on site ranked last (RII= 0.57). This analysis showed that all the listed factors ranked above average which depicts that they all have high frequency of occurrence.
NOTE/KEY:
N: Number of respondents
RII = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of respondents rating an attribute from 1 – 5

Respondents were asked to rate the significance of impact of contractor-related factors influencing time overrun. The responses are shown in table 4.13 below

Table 4.13 Relative Importance Index (RII) showing the ranking of the Significance of impact of Contractor-related factors influencing time overrun on construction projects

Here, table 4.13 revealed the different contractor-related factors influencing time overrun in construction projects with the aim of determining the factor with the most significant impact. It is shown that from table 4.13, thirteen (13) different contractor-related factors influencing time overrun were identified so as to know the most significant contractor-related factor. All the factors showed high significant impact ranged (0.66 – 0.62). From the analysis above, it revealed that the most significant client-related factor influencing time overrun in construction projects is mistakes during construction andinadequate construction planning(RII= 0.66), insufficient number of staff, low productivity of labour, lack of commitment by contractor to consultant instruction, rework of bad quality performance, and shortage of construction materials on site ranked next (RII= 0.65), poor site management, equipment and tool shortage on site, inadequate contractor experience, inappropriate construction methods ranked third (RII= 0.64), poor material handling site ranked fourth (RII= 0.63). Slow information flow between project team members site ranked last (RII= 0.62). This analysis showed that all the listed factors ranked above average which depicts that they all have high significant impact.
NOTE/KEY:
N: Number of respondents
RSI = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of
respondents rating an attribute from 1 – 5.

Respondents were asked to rate the frequency of consultant-related factors influencing time overrun. The responses are shown in table 4.14 below
Table 4.14 Relative Importance Index (RII) showing the ranking of the Frequency of Consultant-related factors influencing time overrun on construction projects

Here, table 4.14 revealed the different contractor-related factors influencing time overrun in construction projects with the aim of determining the most frequent factor. It is shown that from table 4.14, fourteen (14) different contractor-related factors influencing time overrun were identified so as to know the most frequent contractor-related factor. All the factors showed high frequency of occurrence ranged (0.84 – 0.50). From the analysis above, it revealed that the most frequent consultant-related factor influencing time overrun in construction projects is discrepancies between contract documents (RII= 0.84), contract modifications ranked next (RII= 0.75), delay in material approval ranked third (RII= 0.72), delays in costing variation and additional works ranked fourth (RII= 0.70), poor design and unclear specification ranked fifth (RII= 0.69), omissions and error in the bills of quantity ranked sixth (RII= 0.68), slow information flow between project team member ranked seventh (RII= 0.66). Bad contract management and re-measurement of provisional works ranked eighth (RII= 0.65), lack of experience of consultant’s staff ranked ninth (RII= 0.63), slowness in giving instruction and incomplete drawing ranked tenth (RII= 0.62), absence of consultant’s site staff ranked eleventh (RII= 0.60). Poor judgment in estimating time ranked last (RII= 0.50). This analysis showed that all the listed factors ranked above average which depicts that they all have high frequency of occurrence.
NOTE/KEY:
N: Number of respondents
RII = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of respondents rating an attribute from 1 – 5

Respondents were asked to rate the significance of impact of consultant-related factors influencing time overrun. The responses are shown in table 4.15 below

Table 4.15 Relative Importance Index (RII) showing the ranking of the Significance of impact of Consultant-related factors influencing time overrun on construction projects

Here, table 4.15 revealed the different consultant-related factors influencing time overrun in construction projects with the aim of determining the factor with the most significant impact. It is shown that from table 4.15, fourteen (14) different consultant-related factors influencing time overrun were identified so as to know the most significant consultant-related factor. All the factors showed high significant impact ranged (0.79 – 0.60).From the analysis above, it revealed that the most significant consultant-related factor influencing time overrun in construction projects is discrepancies between contract documents (RII= 0.79), delay in material approval ranked next (RII= 0.78), contract modifications, poor design and unclear specification ranked third (RII= 0.73), omissions and error in the bills of quantity ranked fourth (RII= 0.72), bad contract management, delays in costing variation and additional works ranked fifth (RII= 0.71), slow information flow between project team member ranked sixth (RII= 0.69), incomplete drawing ranked seventh (RII= 0.66), re-measurement of provisional works ranked eighth (RII= 0.65), absence of consultant’s site staff and slowness in giving instruction ranked ninth (RII= 0.64), lack of experience of consultant’s staff ranked tenth (RII= 0.62). Poor judgment in estimating time ranked last (RII= 0.60). This analysis showed that all the listed factors ranked above average which depicts that they all have high significant impact.
NOTE/KEY:
N: Number of respondents
RSI = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of
respondents rating an attribute from 1 – 5.

Respondents were asked to rate the frequency of external factors influencing time overrun. The responses are shown in table 4.16 below

Table 4.16 Relative Importance Index (RII) showing the ranking of the Frequency of impact of External factors influencing time overrun on construction projects
External factors RII Rank

Contractual claims 0. 79 1

Slow permits by government agencies 0.61 2

Adverse weather condition 0.61 2

Lack of material market 0.53 3

Labour strike 0.52 4

Community violence and instability 0.51 5

Here, table 4.16 revealed the different external factors influencing time overrun in construction projects with the aim of determining the most frequent factors. It is shown that from table 4.16, six (6) different external factors influencing time overrun were identified so as to know the most frequent client-related factor. All the factors showed high frequency of occurrence ranged (0.79 – 0.51). From the analysis above, it revealed that the most frequent external factor influencing time overrun in construction projects is contractual claims (RII= 0.79), adverse weather condition and slow permits by government agencies ranked next (RII= 0.61), lack of material in market ranked next (RII= 0.53), labour strike ranked next (RII= 0.52). Community violence and instability ranked last (RII= 0.51). This analysis showed that all the listed factors ranked above average which depicts that they all have high frequency of occurrence.

NOTE/KEY:
N: Number of respondents
RII = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1 + 2n2 + 3n3 + 4n4 + 5n5, where; n = number of respondents rating an attribute from 1 – 5

Respondents were asked to rate the significant of impact of external factors influencing time overrun. The responses are shown in table 4.17 below

Table 4.17 Relative Importance Index (RII) showing the ranking of the Significance of impact of External factors influencing time overrun on construction projects

Here, table 4.17 revealed the different external factors influencing time overrun in construction projects with the aim of determining the factor with the most significant impact. It is shown that from table 4.17, six (6) different external factors influencing time overrun were identified so as to know the most significant external factor. All the factors showed high significance of impact ranged (0.79 – 0.51). From the analysis above, it revealed that the most significant external factor influencing time overrun in construction projects is contractual claims (RII= 0.79), adverse weather condition ranked next (RII= 0.54), lack of material in market ranked next (RII= 0.53), community violence and instability ranked next (RII= 0.52). Slow permits by government agencies and labour strike ranked last (RII= 0.51). This analysis showed that all the listed factors ranked above average which depicts that they all have high significant impact.
NOTE/KEY:
N: Number of respondents
RSI = Relative Importance Index. RII = TWV
5N

TWV: Total Weight Value. TWV = 1n1+ 2n2 + 3n3 + 4n4 + 5n5, where; n = number of
respondents rating an attribute from 1 – 5.

4.3.3 Objective 3: Evaluation the effects of time overrun on cost of construction projects
Time and cost data of 47 completed building projects were obtained from consulting quantity surveyors. It has earlier been suggested that for accuracy of predictive models, homogeneity of data is very important (Ogunsemi 2002), hence the study focused on building works. Specifically, the initial and final cost and duration of such projects were obtained from which the time overruns and cost overruns were calculated. The data were limited to projects completed within a five-year period from 2010 to 2014. The data for the study were obtained from Lagos. All the cost overruns used for the study were adjusted to 2014 prices using Consumer Price Index. This was to take care of the fact that the cost data collected were based on different points in time and possibly different economic conditions (Bowen, 1982)
Projects completed within predicted time and estimated budget, those with time underrun and cost underrun were removed. This is because the study only aimed to evaluate the relationship between time overrun and completion cost of construction projects. 43 projects were left. The details are shown below.

Table 4.18 Types of Archival Projects Collected

Table 4.18 showed the details of sample data. Of these samples, the majority are Residential projects with 13 projects (30.2%). Next are Office complexes with 8 projects (18.6%), Educational buildings with 6 projects (14.0%), Hospitals, Hotels, Estates with 3 projects each (7.0%). The next are Commercial buildings, and Shopping Complexes with 2 projects each (4.7%). Recreational projects, Event place and Halls are in the minority with 1 project each (2.3%)

Table 4.19 Cost and Time Data of Archival Projects Collected

Table 4.19 Cost and Time Data of Archival Projects Collected

Out of the 47 projects collected 91.5% representing 43 projects has time overrun and cost overrun. This shows that time overrun is a very frequent phenomenon and is almost associated with nearly all projects in the construction industry. This agrees with Sweis (2013), and Shanmugapriyal and Subramanian (2013).
Table 4.20 Details of Projects surveyed

From table 4.20, the average initial and actual time for construction was 60 weeks and 78 weeks respectively. The longest initial and actual time for construction was 156 weeks and 216 weeks respectively. The shortest initial and actual time for construction was 11 weeks and 14 weeks respectively. Lowest initial and final costs of project are ₦20,500,000 and ₦20,500,000 respectively, the highest initial and actual cost of project are ₦12,877,467,375 and ₦13,123,139,124. The average initial and final costs of projects are ₦1,773,384,770 and ₦1,934,708,639 respectively.

Table 4.21 Time Overrun of Executed Projects

From table 4.21, 9.3% of the projects had less than 10% time overrun, 27.9% had between 10%-20% time overrun and those with time overrun greater than 20% had the highest percentage of 62.8%. This showed that greater percentage of the projects had time overrun greater than 20%.

Table 4.22 Cost Overrun of Executed Projects

Classification
Frequency
Percentage (%)

Table 4.22 revealed the cost overrun of the projects. 65.1% of the projects have less than 10% cost overrun, 14.0% have between 10%-20% cost overrun, while 20.9% has greater than 20% cost overrun
80% of the data were used for developing the model while the remaining 20% were used for validation. This ratio was adapted from Akindele (1990), who used two-third of the original data for calibration and the remaining for validation (Cited by Ogunsemi and Jagboro, 2005). The effect of time overrun on cost of construction project was evaluated by determining the relationship between the time overrun and cost overrun of the archival data using regression models of SPSS. The dependent variable being cost overrun while the independent variable is time overrun. The result of the analysis of different models is as follows:

Table 4.23 Model Summary and Parameter Estimates

Equation Model Summary Parameter Estimates
R2 F df1 df2 Sig. Constant b1 b2 b3
Linear .439 25.021 1 32 .000 -17966119.371 10112551.831
Logarithmic .275 12.121 1 32 .001 -332834318.854 193730587.991
Inverse .151 5.688 1 32 .023 323180033.034 -1506854558.735
Quadratic .465 13.477 2 31 .000 58930549.719 3710671.281 62718.481
Cubic .517 10.690 3 30 .000 -97777230.963 29025400.854 -780609.663 5652.411
Compound .172 6.636 1 32 .015 10743161.648 1.051
Power .208 8.399 1 32 .007 837297.019 1.337
S .176 6.833 1 32 .014 18.410 -12.911
Growth .172 6.636 1 32 .015 16.190 .050
Exponential .172 6.636 1 32 .015 10743161.648 .050

Table 4.23 revealed that all the regression models are significant, but cubic regression has the highest coefficient of determination (R2= 0.517) which is widely accepted as an indication of how well a model fits the population as opined by Chan (1999).
Cubic regression (CUB) C=b0+ b1T + b2T2+ b3T3 Equation 4.1
Where C= Cost Overrun in Naira (₦)
T= Time Overrun in week
b0 = constant; b1, b2, and b3= coefficients
The result of the analysis for cubic regression model is as follows:

Table 4.24 Model Summary of Cubic Regression Model
R R Square Adjusted R Square Std. Error of the Estimate
0.719 0.517 0.468 217651558.7

The result from Table 4.24 shows the summary of the cubic regression analysis which shows that R = 0.719, R2= 0.517, Adjusted R2= 0.468,Standard error of the estimate = 217651558.7,P < 0.05.
Generally, R is the measure of correlation between cost overrun and time overrun. R Square (R2) is the square of the measure of correlation and indicates the proportion of the observed variance in the variation which can be accounted for by this framework. The result of the regression analysis from Table 4.24 showed strong correlation between time overrun and cost overrun of building projects (R= 0.719). This implies that there exists strong positive relationship between time overrun and cost overrun of construction projects.
The R2 value of 0.517 on the other hand is the proportion of the observed cost overrun in the variation which can be accounted for by this equation. Therefore, it could be concluded that this model could account for 51.7% of the cost overrun. This implies that 51.7% of cost overrun can be attributed to time overrun and 48.23% being accounted for by other factors not included in the equation.
The coefficients of the developed regression model is shown in Table 4.25 and its equation is given as equation 4.2

Table 4.25 Coefficients of the DevelopedModel
Unstandardized Coefficients Standardized Coefficients T Sig.
B Std. Error Beta
Time Overrun 29025400.854 15134230.834 1.901 1.918 .065
Time Overrun ** 2 -780609.663 473885.019 -5.596 -1.647 .110
Time Overrun ** 3 5652.411 3159.124 4.544 1.789 .084
(Constant) -97777230.963 118681601.793 -.824 .417

C= -97777230.963 + 29025400.854T – 780609.663T2 + 5652.411T3 Equation 4.2
It is possible to have a framework predicting an outcome but may not do so significantly. The cubic regression procedure made provision for testing the significance of a framework via ANOVA test of difference and hypothesis testing. The tested hypothesis is as stated below and the result presented in Table 4.26.
H0: There is statistically significant relationship between time overrun and cost overrun of building projects
H1: There is no statistically significant relationship between time overrun andcost overrun of building projects

Table 4.26: Summary of ANOVAresult
Developed Model F Sig.
Cubic regression 10.690 0.000
asignificant at p < 0.05.
From Table 4.26, F= 10.690 at p = 0.000. Since the p value is less than 0.05, the null hypothesis (that there is statistically significant relationship between time overrun and cost overrun) can be accepted. Hence, we accept the null hypothesis and can conclude that the model is significant at predicting cost overrun

Validation of the developed framework
To validate the developed framework, techniques that can be applied include the use of R2(value of coefficient of linear determination) for this study, a test for validity of cubic regression model was conducted and the developed model can therefore be presented as valid model for predicting cost overrunfrom time overrun overrun, though not devoid of limitations. Those limitations are expected to be part of future research.
A t-test was carried out between the observed and predicted values to assess their significant differences. The hypotheses tested at 5% significance level were as follows:
H0: There is no significant difference between the observed and predicted values.
H1: There is significant difference between the observed and predicted values.
t-calculated is less than t-tabulated, H0is accepted. This implies a valid model. The t-test carried out indicated that there was no significant difference between the observed cost overrun and the predicted cost overrun as a result of time overrun while the mean of the observed cost overrun and predicted cost overrun were almost the same as shown in table 4.27 below.

Table 4.27 Validation criteria for the model
Project Mean observed Mean predicted t-stat. t.crit.
All 189009295.023 ± 273475890.837 189009295.023 ± 142568756.892 0.000 2.306

Furthermore a regression test was carried out between the observed and predicted cost overrun values the result is shown in table 4.28 below.

Table 2.28 Regression results between the observed cost overrun and the predicted cost overrun
Project R R Square Slope Intercept
All .521 .272 1.00 -2.96E-5

A good model ought to show a high coefficient of determination (R2) while the intercept and slope should be close to 0 and 1 respectively. The regression result shown in table 2.28 below reveals that the model is a good one.

4.4 Discussion of Results
The study focused on assessing the effects of time overrun on construction cost in Lagos State with a view to ensuring that construction projects are delivered to scheduled time and estimated budget. The objectives were to identify and assess the sources and causes of time overrun on construction projects in Lagos State Nigeria; identify and assess the factors influencing time overrun on construction projects in the study area; and evaluate the effects of time overrun on cost of construction projects.
The result of the analysis in Table 4.8 revealed that the most frequent source of time overrun in construction projects is the client (RII= 0.82), followed by contractor (RII= 0.73) which ranked second, consultant ranked third (RII= 0.66). External factors ranked last (RII=0.48). This shows that external factors rarely cause time overrun on construction projects. This explained the increasing involvement and/or interference by project owners. These findings agree with the findings by Pathiranage and Hawaltura (2010), Algharbiet. al. (2007) in Malaysia and Mezher and Tawil (1998) in Lebanon but disagree with Kaminget. al. (1997) in Indonesia and Haseebet. al. (2010) in Pakistan where contractor was identified as the most frequent source of time overrun.
From the analysis in Table 4.9, it shows that client is the source of time overrun with the most significant impact (RII=0.74). This agrees with Dolage and Rathnamali (2013) but at variance with the findings of Sweis (2013), Wei (2010), Kaminget. al. (1997), and Koushkiet. al. (2005) which identified contractor as the most significant source of time overrun. Second on the rank is consultant which ranked third in Table 4.8. Also, third on the rank is contractor which ranked second on Table 4.8. This shows that contractor caused time overrun more frequently than consultant but time overrun caused by consultant has more significant impact than that caused by contractor. This is not unexpected since consultants can make significant changes (such as change orders, re-design, omissions and additions) to the project which would consequently result in time overrun. External factors ranked last which is the same with Table 4.8. This revealed that external factors have the least significant impact on time overrun of construction projects.
The result of the analysis in Table 4.10 revealed that the most frequent client-related factor influencing time overrun of construction projects is owner’s interference which ranked first, followed by delays in payment to contractor which ranked second. Owner-initiated variation ranked third, suspension of work ranked fourth. Unrealistic contract durations and initial requirement ranked last. This showed that unrealistic contract durations and initial requirement rarely caused time overrun. This finding is not surprising since clients can easily modify projects by initiating change orders due to change in taste, change in level of aesthetics desired and financial capacity.
From the result of the analysis in Table 4.11, it is seen that owner’s interference which ranked first in Table 4.10 also ranked first meaning that owner’s interference is the most frequent and most significant client related factor influencing time overrun of construction projects. This is in consonance with the findings of Abdalla and Battaineh (2002) and Ashwini and Rahul (2014). Suspension which ranked fourth in Table 4.10 ranked second, third on the rank are delays in payment (which ranked second in Table 4.10) and owner-initiated variation (which also ranked third on Table 4.10). This means delays in payment and owner-initiated variation occur more frequently than suspension of work but suspension of work has more significant impact on time overrun. This result reinforced the fact that work can still be on-going even when payments are delayed, also, speed of work can be increased to cushion the effect of variations on project duration but the same cannot be done when the work is suspended. Also delays in payment occur more frequently than owner-initiated variation but the two factors has the same significant impact on time overrun. Unrealistic contract durations and initial requirement last in Table 4.11 and 4.10, hence it least cause time overrun and has least significant impact on time overrun of construction projects among the client-related factors. These findings disagree with Dolage and Rathnamali (2013) where delay in progress payment was identified as the most significant factor causing time overrun.
From the result of the analysis in Table 4.12, it shows that insufficient number of staff is the most frequent contractor-related factors influencing time overrun of construction projects. This is followed by inadequate contractor experience, low productivity of labour, poor site management, mistakes during construction, lack of commitment by contractor to consultant’s instructions, poor material handling on site, inadequate construction methods, equipment and tools shortage on site, slow information flow among project team members, inadequate construction planning, rework of bad quality performance and shortage of construction materials on site which ranked last. This finding is somewhat true in relation to Adam et. al.(2014) and Al-Najjar (2008). The finding is as expected since time expended depends on the rate of labour productivity which is largely influenced by the size of workforce and management.
The result of the analysis on Table 4.13 revealed that the contractor-related factors influencing time overrun of construction projects with the most significant impact are inadequate construction planning and mistakes during construction. Insufficient number of staff, lack of commitment by contractor to consultant instruction, low productivity of labour, rework of bad quality performance, and shortage of construction materials on site ranked second, followed by equipment and tool shortage on site, inappropriate construction methods, poor site management, poor material handling site, and slow information flow between project team members which ranked last. This finding is in the same vein with that of Aiyetanet. al. (2008) and it further underscored the importance of adequate planning in project success.
From the result of the analysis in Table 4.14, it is shown that discrepancies between contract documents is the most frequent consultant-related factor influencing time overrun of construction projects, followed by contract modifications which ranked second. Delay in material approval ranked third followed by delays in costing variation and additional works, poor design and unclear specification, omissions and error in the bills of quantity, slow information flow between project team member, bad contract management, re-measurement of provisional works, lack of experience of consultant’s staff, slowness in giving instruction, incomplete drawing, absence of consultant’s site staff, and poor judgment in estimating time which ranked last.
The result of the analysis shown on Table 4.15 revealed that the consultant-related factor influencing time overrun with the most significant impact is discrepancies between contract documents, followed by delay in material approval, contract modifications and poor design and unclear specification. Omissions and error in the bills of quantity ranked fourth followed by bad contract management, delays in costing variations and additional works, slow information flow between project team members, incomplete drawing, re-measurement of provisional works, absence of consultant’s site staff, slowness in giving instruction, and poor judgment in estimating time which ranked last. This result is not outrageous since discrepancies between contract documents can lead toserious misunderstanding. The result is supported by the findings of Jeykanthan and Jayawardena (2012)
From the result of the analysis in Table 4.16 and Table 4.17 it shows contractual claims as the most frequent and most significant external factor influencing the time overrun of construction projects From Table 4.16, slow permits by government agencies and adverse weather condition ranked second followed by lack of material in market, labour strike and community violence and instability ranked last. This revealed that community violence and instability is the least external factor influencing time overrun of construction projects. From Table 4.17, adverse weather condition, lack of material in market ranked second and third respectively. Community violence and instability ranked fourth followed by slow permits by government agencies and labour strike which ranked last. Hence, slow permit by government agencies and labour strike are the external factors influencing time overrun of construction projects with the least significant impact.
Though some factors are more frequently occuring and mentioned than others, this does not necessarily imply that they are more influential in determining the scale of time overrun. Indeed, the frequency by which a particular cause is mentioned or occured may instead offer an indication of it being easily observed as opposed to having greater impact (Adam et. al., 2014).
In the above analysis, some findings agree and some disagree with previous researches. However, this is not surprising since the causes and effects of time overrun factors in construction industry vary from country to country due to environmental, topographical and technological constraints (Sweis, 2013).Kikwasi(2012) also buttressed this by proposing that major causes of time overrun seem to differ significantly from one country to another. In anticipation of the effect of globalisation and the technological difference between developing and developed countries, as this research has done for the Nigerian construction industry, it is necessary to identify the actual cause of time overrun in order to reduce its impact in any construction project.

5. SUMMARY OF FINDINGS, CONCLUSION AND RECOMMENDATION
5.1 Conclusion
The study focused on assessing the effects of time overrun on construction cost in Lagos State with a view to ensuring that construction projects are delivered to scheduled time and estimated budget. The objectives were to identify and assess the sources and causes of time overrun on construction projects in Lagos State Nigeria;identify and assess the factors influencing time overrun on construction projects in the study area; and evaluate the effects of time overrun on cost of construction projects.
This study identified different sources of time overrun in construction projects to be client, contractor, consultants and external factors. The most frequent source of time overrun was identified to be client, followed by contractor, consultant and external factors in that order. The source of time overrun with the most significant impact was identified to be client, followed by consultant, contractor, and external factors in that order. This implies that contractor cause time overrun more frequently than consultants and external factors but consultants cause time overrun more significantly than contractor and external factors.
Client-related factor with the most significant impact on time overrun is owner’s interference followed by suspension. Owner’s interference followed by delays in payment are the most frequent client-related factors influencing time overrun. Unrealistic contract durations and initial requirement is the least frequent factor and has the least significant impact on time overrun.
The most frequent contractor-related factor is insufficient number of staff, followed by inadequate contractor experience and low productivity. Rework of bad quality performance and shortage of construction materials on site ranked as the least frequent. However, the contractor-related factors with the most significant impact are inadequate construction planning and mistakes during construction followed by insufficient number of staff and lack of commitment by contractor to consultant instruction. Poor material handling on site and slow information flow between project team members have least significant impact on time overrun among contractor-related factors.
Consultant-related factors with the most significant impact on time overrun are discrepancies between contract documents, contract modifications, and delay in material approval. Absence of consultant’s site staff and poor judgment in estimating time are the least frequent factors. Those with the most significant impacts are discrepancies between contract documents, delay in material approval, contract modifications and poor design and unclear specification. Lack of experience of consultant’s staff and poor judgment in estimating time are the factors with the least significant impacts on time overrun.
The most frequent external factors influencing time overrun on construction projects are contractual claims and slow permits by government agencies. Labour strike and community violence are the least frequent external factors influencing time overrun of construction projects. Contractual claims and adverse weather condition are the external factors which most significantly influence time overrun of construction projects while slow permits by government agencies and labour strike are the least significant.
The effect of time overrun on completion cost of construction projects was evaluated. Having considered other regression models, a cubic regression equation has highest predictive power, the result is:
C= -97777230.963 + 29025400.854T – 780609.663T2 + 5652.411T3, R= 0.719, R2= 0.517
The model developed was statistically significant. The correlation coefficient (R) was 0.719, therefore there exists a strong positive relationship between time overrun and cost overrun; and coefficient of determination (R2) was0.517, therefore 51.7% of cost overrun is being accounted for by time overrun and 48.3% being accounted for by other factors not included in the equation like fluctuation claims, variation claims and claims for loss and expense which can increase a contract sum without affecting the duration of the project.However, this reveals that time overrun is the major factor leading to cost overrun. Hence, the extent of the effect of time overrun on completion cost of building projets has been established.
To ensure that this model can be used as an industry standard, constant updating of the model using current project information is inevitable.

5.2 Recommendation
Based on the findings of this research and the conclusions drawn, the following recommendations are proposed to help the time performance and enhance delivery of construction projects within proposed duration:
1. Clients, especially the uninformed ones should be enlightened as regards the implication of their actions like interferences and delays in payment since they are the most frequent and significant source of time overrun on construction projects.
2. Clients should ensure adequate cash flow to avoid suspension of work which is a major factor influencing time overrun on construction projects
3. The experience of tenderers and staff capacity should be considered in awarding contract as these are part of the most frequent factors influencing time overrun.
4. Consultants and contractors must engaged in proper planning so as to avoid delays. Also, consultants should harmonise all contract documents and parameters amended during tender negotiation and thereafter as and when due and such changes should be communicated to all parties accordingly.
5. Quantity Surveyors should use the model created to advise the client and the consultant team on the financial implication of time overrun
6. Designer should ensure timely preparation of drawings and specifications so as to enhance the accuracy of the quantity surveyor’s estimation of projects’ financial implication and reduce variation claims by contractor due to unclear drawings and specifications.

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