Choice Experiment Framing and Incentive Compatibility: observations from public focus groups

The hypothetical nature of choice modelling surveys makes it difficult to enforce incentive compatible properties. It is thought that bias may result through strategic behaviour and untruthful responses, given that the hypothetical choice scenarios and payment structure are not binding. This study examines three methods of addressing incentive compatibility through survey framing: (1) a statement of consequence; (2) use of an ‘honesty’ script that openly explains how the data are to be analysed and used; and (3) use of a provision rule that defines how survey outcomes relate to actual implementation. Focus groups, involving members of the public, were held to investigate participants’ reactions to the three framing treatments. The provision rule emerged as the preferred treatment in terms of being more realistic than the alternatives. The rule did not need to be 100% binding to have the desired effect of inducing realism. However, the participants did not believe that their responses to the choice scenarios would have changed between framing treatments. Empirical testing is required to determine if this is actually the case. Other reassuring results were found in relation to how participants interpreted the general choice scenario instructions, particularly in terms of answering questions independently and as an individual consumer. This provides evidence that respondents make choices in response to the questions as they are intended by the researcher.