| Abstract: |
The somewhat ad-hoc method of certainty calibration, based on self-stated
preference certainty follow-up questions, has been found to be a successful
method of eliminating or reducing hypothetical bias in stated preference
studies. But is the preference certainty really context dependent, or do some
subjects tend to always state themselves as certain regardless of the context,
i.e. is the preference certainty dependent on a systematic unobservable
individual-specific effect? This question is empirically analyzed in this
paper using data where a preference certainty question follows a hypothetical
willingness to pay question, in two different contexts. Estimated bivariate
probit models provide no evidence for systematic individual-specific answers
to the preference certainty follow-up questions of different contexts. Since
there is no support for a randomly self-stated preference certainty either,
this result is deemed to increase the credibility of certainty calibration. |