On the external validity of construction bidding experiment

The external validity of experimental studies and in particular, the subject pool effects have been much debated among researchers. The common objections are that the use of student as experimental subjects is invalid as they are likely to be unrepresentative. This paper addresses this methodological aspect in building economics research. It compares the bidding behavioural patterns of experienced construction executives (professionals) and student subjects through replication of a bidding experiment that aimed at testing theories. The results show that the student subjects’ bidding behavourial patterns, in terms of decision to bid and mark-up decision, are sufficiently similar to that of the professionals. This suggests that the subject pool per se is not a threat to the external validity of the bidding experiment. In addition, the demonstrated practicality of an experimental approach in testing theories should lead to more use of experimental studies with student subjects in building economics research. It is suggested that experimental and field findings should be seen as complementary in building economics research, as advocated in social sciences.