Calibrating hypothetical willingness to pay responses

Experimental data comparing hypothetical and real dichotomous choice responses for two different goods were used to estimate a statistical bias function to calibrate the hypothetical yes responses. The probability that a hypothetical yes response would be a real yes response was estimated as a function of the individual's self-assessed certainty of the hypothetical yes response (assessed on a 0-10 scale) and a variable representing the price level. Without calibration the hypothetical yes responses significantly exceeded the proportion of real yes responses, but after calibration the null hypothesis of no difference between hypothetical and real responses could not be rejected in any of the experiments.