JOURNAL OF POLYTECHNIC-POLITEKNIK DERGISI, cilt.19, ss.175-183, 2016 (ESCI İndekslerine Giren Dergi)
In the construction industry, increasing competition environment has led to decrease in the profit share of the projects. Accordingly, importance of construction cost estimation works has been increased for both the employer and the contractor. The purpose of this study has been to determine and compare the construction cost estimations obtained by widely used databases, "unit price method" (UPM) and "unit area cost method" (UACM) in Turkey. For this purpose, construction data from 420 projects, which were procured in accordance with the Public Tender Law no 4734 by the Turkish Ministry of Environment and Urbanism and completed between 2003 and 2011, were reviewed. Root mean square error (RMSE), mean absolute percentage error (MAPE) and coefficient of determination (R-2) were calculated for the comparison of actual and estimated cost values. Consequently, RMSE and MAPE values from UPM were underestimated with the ratio of 13.57% and 1.73% than UACM. Although UPM showed better performance than the UACM, it is not at a satisfactory level.