Construction tender bid variability in Singapore

Abstract

This paper explores the effect of bid variability on inaccuracies in consultant estimates and on winner's curses for public sector construction tenders in Singapore. Data has been collected regarding all public sector construction tenders, for projects of a variety of government departments and ministries, submitted over a 12-month period of 1989-90. This number some 1256 tenders that have been awarded. In addition a second sample of data has been collected of details of differences between pre-tender estimates and lowest bids for some of these government agencies. Details of all of these field data are presented in the paper. Analysis of these data shows the extent of winner's curse and estimate inaccuracy for this sample of projects. This has been compared with data from other samples in the UK, USA and Australia showing some local differences. Analysis of sub-samples by time, location, client body, work type, and number of bidders is used in deriving some conclusions of the causes of bid variability and thus winner's curse and pre-tender estimating accuracy, in this part of the world. The application of this knowledge in cost engineering would be to both consultants' and contractors' advantage in reducing winner's curse and estimate inaccuracy respectively.