Recent project management related researches on construction duration modelling have received a considerable attention among academicians all over the world. There are various factors affecting construction duration such as number of houses, drawing type, project priority and complexity, financial risks, location, and climatic factors. It was determined that number of projects delayed within overall TOKI projects (2800) is the highest for housing projects (1530) by 25.71% while the number of housing projects delayed within itself was found to be 720 (47.06%). Therefore, it was decided to investigate the factors effecting construction duration for only housing projects. The main objective of this study was to propose a novel model involving eight additional factors chosen from the literature review, TOKI interviews and TOKI documents to estimate more accurate total construction duration which was named hereby Ideal Duration. The proposed model considers baseline duration which utilises three factors and calculates ideal duration by using certain assessment criterion for each additional eight (in total eleven) factors by using SPSS 25.0 and statistical methods. Data analysis was performed by multiple regression analysis, CHAID and CART, respectively. Findings were interpreted according to confidence interval of 95% (p<0.05). Findings of the study have shown that eight, seven, and five factors out of eleven were significantly affected the baseline duration for regression, CHAID, and CART analysis, respectively. The cut-offs and standard errors were calculated to test and to validate all three statistical methods. After that, all significant factors were discussed for each statistical method. By using significant factors for each method, ideal duration for housing projects has been calculated for 1530 projects again and number of delayed housing project were recalculated. It has been observed that the number of delayed housing projects has decreased prominently compared to the existing case before the model implementation. In conclusion, the findings supported that proposed model is a valid and reliable tool to estimate the ideal duration for housing projects.
Anahtar Kelimeler: Project Management, Construction Time Planning, Factors Affecting Construction Duration, TOKI, Regression Analysis, CHAID and CART Analysis