Construction delays causing risks on time and cost - a critical review

There is an increase in the number of construction projects experiencing extensive delays leading to exceeding the initial time and cost budget. This paper reviews 41 studies around the world which has surveyed the delay factors and classified them into Groups. The main purpose of this paper is to review research which has categorized the causes responsible for time delays and cost overruns in projects. The intention was to see whether these causes are valid for projects being executed in Sabah East Malaysia allowing a mitigation plan to be prepared. The collected list has 113 causes for delays which were categorized into 18 different groups. Most of the research has analysed the responses from Questionnaire surveys. The collected data are used to rank the problem factors. The data are further used to investigate and analyse the reported “Importance Index, Frequency Index, Severity Index, Relative Importance Index, Relative Importance Weight, Weighted Average, Mean, Standard Deviation and Variance”. The collective comparison has revealed that the ranking given by all the researchers is not the same. Further each and every study has different rank ratings from different group. This review paper attempts to provide an updated compilation of the earlier studies on ranking of the delay causers, which are never similar and constant for universal projects. From the critical review, it is concluded that this type of research requires a different method or approach to generate meaningful answers and that there is a strong case against opinion surveys.