The influence of design quality on productivity in construction

Abstract

In many countries, the productivity in the design office has been a neglected field compared with the outpourings of research and theory on productivity in construction. It may thus be useful to review the state of the art in construction research, as there are parallels to be drawn with the design environment. The author used ten construction projects to research the influence of design quality on the productivity in construction. The ten projects were all designed by the author. The data were collected after the construction phase and the direct costs were identified with rework(including redesign), repair, and replacement. Finally the author gives four equations for forecasting quality problems related to design in construction. The methods of analysis used are statistical, optimization, simulation and fuzzy logic. Analysis of the data indicates that in construction the deviations on projects accounted for an average of 12.4% of the total project cost. Furthermore, design deviation average 78% of the total number of deviations, 79% of the total deviation costs, and 9.5% of the total project cost. Since design cost is a small percentage of total costs, and an increase in design expenditure can frequently reduce total life cycle costs, it is important to research the influence of design quality on productivity in construction.