Thesis is submitted in partial fulfilment for the degree of Master of Science (Building) to the Faculty of Engineering and the Built Environment, School of Construction Economics and Management at the University of the Witwatersrand, Johannesburg, 2017 / The construction industry in many countries is faced with challenges when it comes to construction project delivery and this may be due to various factors, which are identified in the research. (Memon, et al ,2010), categorized the challenges faced in the construction industry as; delays in completing projects on time, expenditure exceeding budgets as well as poor quality. The purpose of the research is to determine the impact of unrealistic initial construction programmes on time performance on projects. The research Investigates how project managers or project planner determine the initial construction periods. Investigate how the three industry participants i.e. the contractor, the consultants, and the client contribute to project delay due to unrealistic construction time periods. And further investigates what can be done to assist inexperienced consultants in determining construction time periods. This study addresses factors that affect project time performance, with the focus on the initial estimated contract duration. A mono method quantitative research was selected and used, to identify the factors that affect timely completion of projects. 33 out of 70 respondents responded to the questionnaire. Through the analyses of questionnaires, the research reports on how industry professionals use existing construction guidelines in determining the construction duration as well as the impact of programming on project performance. From numerical data obtained from the respondents, 43% believes that the client determines the construction duration, while 38% says it’s the consultant project manager and only 14% says it’s the contractor. The client, through his representative determines the construction duration. There are no regulated or standardized guidelines for determining the construction duration, this is dependent on the project managers experience. Though there are other factors that causes construction delays, and not specifically the initial programme, all these factors can be directly linked to this programme. / XL2018