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

OBJECTIVES

This study compared quantitative measures of risk tolerance between 2 preference-elicitation methods: a discrete-choice experiment (DCE) and a probabilistic threshold technique (TT) exercise.

METHODS

A survey offered benefit-risk trade-offs pertaining to devices used in revascularization procedures for peripheral artery disease. Survey design features included alternating the sequence of DCE and TT exercises, testing 2 risk-communication approaches, and using 2 DCE experimental designs. The risk tolerance metric was the maximum-acceptable risk (MAR) increase in 5-year mortality, above an 8% baseline risk, 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 was observed for approximately half (48.2%) of the sample.

CONCLUSIONS

Although 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.