1. Independent Software Developer, P.O. Box 21368, Christchurch, New Zealand (corresponding author). E-mail: dcattell@carwise.info
2. Professor and Head of Department, Dept. of Construction Economics and Management, Faculty of Engineering and the Built Environment, Univ. of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa. E-mail: bowenpa@ebe.uct.ac.za
3. Professor of Construction Economics and Management, School of the Built Environment, Heriot-Watt Univ., Edinburgh, U.K. E-mail: a.p.kaka@sbe.hw.ac.uk