Measuring the impact of conquas scores on construction duration of projects in Singapore

Abstract

The introduction of the Construction Quality Assessment System has helped in improving the quality of buildings in Singapore. However, with higher workmanship, project duration may be affected adversely. This study aims to investigate the impact of CONQUAS score on duration of projects carried out in Singapore. Furthermore, it proposes a formula to estimate project duration based on contract value and CONQUAS score. Data is collected from 39 local projects finished from 2000 to 2010 whereby 30 data sets are used for multiple regression analysis and 9 data sets are reserved for model validation. The analysis results show that there is a relationship between CONQUAS score and project duration expressed in the form of T = 11.123*C0.143*S0.85. To ensure the assumptions of multiple regression are not violated, various tests were carried out with SPSS including the search for influential data, multicollinearity and heteroscedasticity. With 9 test cases being run on the proposed model, the mean absolute percentage error is found to be 30%. This implies that there are other factors that are not taken into account in the prediction model. It is suggested for the future research that more factors influencing project duration should be investigated to be included in this model. Lastly, due to the impact of high workmanship target perceived from the data analysis, a theoretical framework is proposed to help owner and project manager in determining a feasible CONQUAS score target at the planning and design stage of construction projects.