The first time is the hardest: A test of ordering effects in choice experiments

This paper addresses the issue of ordering effects in choice experiments, and in particular how learning processes potentially affect respondents’ stated preferences in a sequence of choice sets. In a case study concerning food quality attributes of chicken breast filets, we find evidence of ordering effects in a sequence of 16 choice sets, where the last 8 choice sets are identical to the first 8. The overall preference structure is found to differ significantly between the two identical sequences of choice sets, and significant increases in marginal WTP are found for two out of four attributes. We find a reduction in the error variance for the last 8 choice sets relative to the first 8 choice sets. In particular, this difference is ascribed to the first choice set obtaining a significantly higher error variance than all succeeding choice sets, suggesting institutional learning rather than preference learning effects underlying the observed ordering effect. This is further supported by the fact that the differences in WTP become insignificant when removing the first choice set from the analysis. We find no evidence of fatigue, and we argue that our findings cannot be explained by starting point or strategic behavior effects.