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This paper aims to focus on developing a baseline model for time overrun.

Information on 321 completed construction projects used to assess the predictive performance of two statistical techniques, namely, multiple regression and the Bayesian approach.

The eventual results from the Bayesian Markov chain Monte Carlo model were observed to improve the predictive ability of the model compared with multiple linear regression. Besides the unique nuances peculiar with projects executed, the scope factors initial duration, gross floor area and number of storeys have been observed to be stable predictors of time overrun.

This current model contributes to improving the reliability of predicting time overruns.

Time overruns are commonplace within the construction industry. These result in deception because project managers critically assess the economic and financial viability of a project before implementation. Forecasting the likelihood of time overruns will not only lead to a reconsideration on the decision to build but also help put in place the necessary control measures – exactly what this research achieved.

The paper argues that rather than depending on the critical failure factors that are unknown at the pre-contract stage to forecast the likelihood of occurrence, it will be more useful to rely on project attributes that are known before contract signing. A multiple linear regression analysis is used for the model development based on ten independent variables.

About 86.6 per cent of all the projects experienced time overruns. The mean time overrun is 106.5 per cent. Initial contract sum, initial duration, gross floor area, contractor class D2K2, competitive tendering, sole sourcing and single-storey buildings explained about 44.7 per cent of the variations within time overruns, with a mean absolute percentage error of 60.7 per cent.

The predictive accuracy of the model can, in practice, be tested after the completion of a project by comparing the actual project schedule with the planned schedule. Any disparity in the expected outputs should result in a reassessment of the significant independent variables to improve the forecasting abilities of the model.

The model is expected to be very useful at the pre-contract stage when detailed designs are unavailable. As a decision support system, it will help the practitioners and decision-makers make informed decisions while minimizing the time and resources spent to arrive at these decisions.

This research presents a unique opportunity to forecast the likelihood of time overruns within the building sector based on project attributes that are known before the contract-signing phase.

In Ghana, the duration of construction projects from inception to completion is becoming a great concern, recently, especially among clients and beneficiaries, because of the rising interest rates, inflation, development plan targets, among other factors. Hence the need to understand the causes of delays and cost overrun in the construction sector has become more important than ever. This study therefore aims to identify the major factors underlying time and cost overruns in projects related to the education sector in Ghana to proffer practical solutions in addressing them.

The study conducted a survey among clients’ consultants and representatives of the contractors working on about 60 government school projects. A relative importance index was used to determine the relative effects of the factors causing construction time and cost overruns.

The key factors causing construction time overrun were: financial problems, unrealistic contract durations imposed by clients, poorly defined project scope, client-initiated variations, under-estimation of project cost by consultants, poor inspection/supervision of projects by consultants. Other factors were underestimation of project complexity by contractors, poor site management, inappropriate construction methods used by contractors and delays in the issuance of permits by government agencies. Factors affecting cost overruns were financial difficulty by client, delays in payments of completed works, variations in designs, lack of communications plans, poor feasibility and project analysis, poor financial management on site and material price fluctuations.

The research was limited to only the educational sector projects.

Practically, this study highlights for the construction sector the critical factors causing project time and cost overruns in Ghana. Identification of these factors provides the basis for pragmatic solutions to enhance the chances of project success.

The identification and solutions to project time and cost overruns, especially for educational sector projects, contribute toward making public goods more affordable and accessible to most citizens, particularly in developing countries.

This study contributes to the debate on factors causing project time and cost overruns in the construction sector especially from a developing country’s perspective.

The purpose of this paper is to explore the impact that cost overruns and time delays exert on large public construction projects to clarify how past and current research regard factors causing cost overruns and time delays in large public construction projects.

This paper, which is based on an analysis of a literature selection consisting of 40 journal articles, investigates and ranks the occurrence of and the explanations for cost overruns and time delays in large public construction projects. The study makes use of a kiviat diagram/radar chart in order to visualize multivariate data.

Aggregated rankings of important causes of cost overruns and time delays are reported. These show a strong emphasis on the management aspect as a primary cause of cost overruns and delays. Additionally, there seems to be a trend toward deemphasizing the role of financial considerations in explaining cost overruns and delays. It is argued that there needs to be a more rigorous assessment of the impact that each factor has on cost increases and delays based on factual observed data as opposed to retrospective accounts from questionnaire respondents.

Only public construction projects have been considered. The results will not be directly applicable to privately funded construction projects and/or projects of a smaller size.

The use of trend data, as illustrated in a kiviat diagram, showing how different ranking factors causing cost overruns and time delays has changed in importance over time.

We investigate causes for the cost overrun and delay of the railway project Stuttgart 21. Besides, we try to forecast the actual costs and completion date at an early stage.

The results of exploratory research show the causes for the cost overrun and delay of Stuttgart 21; we compare our findings with other railway projects. To estimate the costs at an early stage, the reference class forecasting (RCF) model is applied; to estimate the time, we apply an OLS regression.

We find that the following causes are relevant for the cost overrun and delay of Stuttgart 21: scope changes, geological conditions, high risk-taking propensity, extended implementation, price overshoot, conflict of interests and lack of citizens' participation. The current estimated costs are within our 95% confidence interval based on RCF; our time forecast underestimates or substantially overestimates the duration actually required.

A limitation of our approach is the low number of comparable projects which are available.

The use of hyperbolic function or stepwise exponential discount function can help to give a clearer picture of the costs and benefits. The straightforward use of the RFC for costs and OLS for time should motivate more decision-makers to estimate the actual costs and time which are necessary in the light of the rising demand for democratic participation amongst citizens.

More realistic estimates can help to reduce the significant distortion at the beginning of infrastructure projects.

We are among the first who use the RCF to estimate the costs in Germany. Furthermore, the hyperbolic discounting function is added as a further theoretical explanation for cost underestimation.

Construction projects within Malaysia are plagued by time overruns that can transform what should have been successful projects, into those incurring additional costs, disagreements, litigation and in some cases abandonment. To help better understand this problem, the purpose of this paper is to investigate Malaysian project characteristics in relation to time overruns.

In total, 150 Malaysian quantity-surveying organisations provided data relating to recent projects they have worked on. Project characteristics considered in analysis are new build and refurbishment, public and private sectors, procurement methods used, nature of projects and tendering methods.

Public sector projects were found more prone to overruns than those in the private sector; refurbishment projects experienced better time performance than new build; construction management demonstrated better time performance than design-build or traditional procurement; and infrastructure projects/negotiated tendering, performed better than selective/open tendering, respectively. The study also developed a linear model to predict project duration, based on contract period.

The study adds a geographically specific detailed analysis to the extant literature of project performance generally and to that of time overruns more specifically.

Findings provide stakeholders with information that may help mitigate the frequency of project delays among construction projects, especially in Malaysia.

The analysis and modelling of time overrun in relation to Malaysian project characteristics in this way is novel.

The delivery of construction projects in Malaysia is plagued by time overruns, which turns what should have been successful projects into those incurring additional costs, or money-losing ventures; as well as leading to various other unexpected negative effects and faute de mieux situations. The purpose of this research is to assess those factors leading to time overrun in Malaysian construction projects. The perceptions of public and private sectors, contractors, clients, and consultants are compared relative to a list of factors derived from the review of extant literature in project delay.

The research data were collected through an industry-wide questionnaire survey circulated across the Malaysian construction industry. The research develops a list of 84 time overrun factors. Responses were collected from 49 clients, 51 contractors, and 105 consultants, to explore and analyse the major factors that are responsible for causing time overrun based on sectors (public and private), organisations (clients, contractors and consultants) and professional roles.

Project delays beyond contract dates are predominantly caused by contractors and are usually associated with financial factors. “Cash flow problems faced by the contractors” was found the major factor, which contributed to project delays, whereas “storage on site” was seen as the least significant factor.

It is noteworthy that the findings in this research have a regional focus; it is, therefore, suggested that readers from other sections of the world exercise caution in applying the findings. As it is believed that every construction industry has its nature, culture and regulations, these factors can change as a result of such differences.

This research provides stakeholders with information on factors, which, if properly understood, can make project delays less likely.

Modeling represents the art of translating problems from an application area into tractable mathematical formulations whose theoretical and numerical analysis provides insight, answers and guidance useful for the originating application. The purpose of this paper is to determine the causal causes of schedule overrun and cost escalation of highway projects in Egypt in order to be used as independents variables in mathematical models for predicting the percentages of schedule overrun and cost escalation of such projects in Egypt.

A survey of a randomly selected samples yielded responses from 40 owners, 15 consultants and 56 contractors. The survey includes 38 schedule overrun factors and 26 cost escalation factors. The effectiveness degree of the identified factors has been identified by the triangle fuzzy approach.

The results of the survey show that “contractor’s technical staff is insufficient and ineligible to accomplish the project” is the most important cause of schedule overrun, while the major cause of cost escalation is inadequate preparation of the project concerning planning and execution.

The main contribution of this study is predicting the percentages of schedule overrun and cost escalation of highway projects in Egypt. Through the application of the linear regression analysis method and statistical fuzzy theory, four predictive models have been developed and it has been noted that the linear regression-based model shows prediction accuracy better than statistical fuzzy-based model in predicting percentages of schedule overrun and cost escalation.

It is estimated that more than half of the construction industry’s projects encounter significant cost overruns and major delays, resulting in the industry having a tarnished reputation. Therefore, it is crucial to identify key project cost and schedule performance factors. However, despite the attempts of numerous researchers, their results have been inconsistent. Most of the literature has focused solely on the construction phase budget and time overruns; the engineering/design and procurement phase costs and schedule performances have been rarely studied. The paper aims to discuss these issues.

The objective of this study was primarily to identify and prioritize engineering, procurement and construction key performance factors (KPFs) and to strategize ways to prevent performance delays and cost overruns. To achieve these objectives, more than 200 peer-reviewed journal papers, conference proceedings and other scholarly publications were studied and categorized based on industry type, physical location, data collection and analysis methods.

It was concluded that both the time required to complete engineering/construction phases and the cost of completing them can be significantly affected by design changes. The two main causes of delays and cost overruns in the procurement phase are construction material shortages and price fluctuations. Other factors affecting all phases of the project are poor economic condition, equipment and labor shortages, delays in owners’ timely decision making, poor communication between stakeholders, poor site management and supervision, clients’ financial issues and severe weather conditions. A list of phase-based strategies which address the issue of time/cost overruns is presented herein.

The findings of this study address the potential confusion of the industry’s practitioners related to the inconsistent list of potential KPFs and their preventive measurements, and pave the way for the construction research community to conduct future performance-related studies.

Being able to predict the likelihood of a project to overrun its cost before the contract signing phase is crucial in developing the required mitigating measures to avert it. Known parameters that permit the timely prediction of cost overrun provide the basis for such predictions. Therefore, the purpose of this paper is to develop a model for forecasting cost overruns.

Ten predictive variables known before the contract signing phase of a project are identified. Based on a survey approach, information on 321 educational projects completed are compiled. A multiple linear regression analysis is adopted for the model development.

Five variables – initial contract sum, gross floor area, number of storeys, source of funds and contractors’ financial classification are observed to influence cost overruns. The model, however, yields a fairly weak coefficient of determination with a mean absolute percentage error of 30.22 and 138 per cent, respectively.

The model developed focussed on data only educational projects sampled from three out of the ten administration regions in Ghana based on a purposive sampling approach.

Policy makers and construction managers working on public projects stand to gain tremendous assistance in formulating and strengthening their own in-house cost forecasting at the precontract phase based on “what if” analysis to generate various alternative predictions of cost overruns.

Considering the innate nature of cost overruns within the Ghanaian construction industry often resulting to project abandonment, this research presents a unique dimension for tackling cost overruns based on a predictive approach.