Ranking and Prediction Formula of Time Waste Causes in Residential Building Projects by LASSO Method

One of the effective ways in reducing time is eliminating or reducing time wastes. Wastes are activities and events that are prolonging the process of producing but would not provide any value-added. For identification, after literature review, interview and thematic analysis were used and according to three factors presence in executing, controllability and direct effect on time, 8 causes were chosen among 35 ones. After that, by distributing questionnaire and using LASSO method, causes ranking and the formula of time waste prediction were obtained. Performing most tasks in site, rework and contractor delay were found out as the most important causes in wasting time. The reason of uniqueness of this paper is using LASSO method for ranking and providing a formula for time waste prediction that not provided in any internal or external articles before now. This prediction is useable 5 to 7 floor residential building projects. According to formula if any 8 causes exist in project process, the amount of waste will be 38% of executing time. By quantifying the amount of time waste, decision making about how to deal with causes is simpler.