1. a Department of Construction Economics and Management , University of Cape Town , Private Bag, Rondebosch, 7700, South Africa E-mail:
2. b School of Civil Engineering, Surveying and Construction , University of KwaZulu Natal , King George V Avenue, Durban, 4001, South Africa E-mail:
3. c School of the Built and Natural Environment , Glasgow Caledonian University , Cowcaddens Road, G4 OBA, Glasgow, UK E-mail: