Means Can Be Deceiving: Comparing and Contrasting Risk-Tolerance Estimates from a Discrete-Choice Experiment and a Threshold Technique Exercise.

Objective: This study compared quantitative measures of risk tolerance between two preference-elicitation methods; a discrete-choice experiment (DCE) and a probabilistic threshold technique (TT) exercise.

Methods: A survey offered benefit-risk tradeoffs pertaining to devices used in revascularization procedures for peripheral artery disease. Survey-design features included alternating the sequence of DCE and TT exercises, testing two risk-communication approaches, and using two DCE experimental designs. The risk-tolerance metric was the maximum-acceptable risk (MAR) increase in 5-year mortality above 8% that patients would accept to choose a device offering lower repeat-procedure risks. DCE data were analyzed with mixed-logit models, and TT data were analyzed with interval regressions. Sensitivity analyses were conducted to examine the impacts of survey-design features.

Results: For the full sample (N=249), MARs from the DCE and TT differed by <1 percentage-point (DCE: 13.0%; TT: 13.8%). MAR estimates were not significantly influenced by the risk-communication approach or experimental-design; however, order of DCE and TT mattered. After removing the influence of DCE and TT order, the mean MARs still differed by <1 percentage-point (MAR among those completing DCE first (n=123): 14.3%; MAR among those completing TT first (n=126): 13.7%). Although convergent validity was found at the sample level, discordance (> 2 percentage points) between individual-level DCE MAR and TT MAR were observed for approximately half (48.2%) of the sample.

Conclusions: While there was concordance between DCE and TT mean MAR estimates at the sample level, at the individual level, only half of the respondents had an absolute difference of 2 percentage-points or less.