Preliminary Cost Estimation Modeling for School Buildings in Sulaimani Governorate

Abstract

Cost estimation for any construction projects at the early stage is a significant attempt, which has a main role in the success of the construction projects, because estimation at the early stage before design is very desired for decision maker to decide whether to start or not according to available budget. All parties involved in construction work as (owners, engineers, contractors and others) pay a great attention to this stage where limited information is available with no drawings or designs even no specifications. The objective of this research is to derive a model relating the cost of project as awarded with several independent variables (parameters) which are; site area, building area, duration(days), earthwork, area of doors and windows, number of floors, number of columns, distance from the city center(km), by utilizing linear regression techniques. The research methodology consists of data collection of 52 school building projects from public sectors which carried out between 2007 and 2014 in Sulaimani governorate. The models have been developed by applying Excel program and Minitab 19 software, then the models have been summarized and best one has been selected. Also, several statistical procedures have been conducted such as R2, R2- adjusted and two sample t-test were used to select more reliable equation. To find out the accuracy of each developed model, the author calculated mean absolute percentage error (MAPE). The range was between 25.3% and 46%. The R2 was between 0.87 and 0.977 and also the ρ-value from two sample t- test was between 0.891 and 0.991.

Keywords

• accuracy; cost; estimation; model; pre-design; regression.