Introduction

The purpose of this study was to gain insight into the decision-making strategies individuals used when evaluating pairs of SF-6Dv2 health states in discrete choice experiments (DCEs).

Method

This was a qualitative, cross-sectional, non-interventional study consisting of one-on-one interviews where participants used a think-aloud approach to compare SF-6Dv2 health states in DCEs. They then shared details on their decision-making process. Thematic analysis focused on overall comprehension and cognitive strategies used to compare health states and make decisions.

Results

Participants (n=40) used three main strategies when completing DCEs: 1) trading; 2) reinterpretation; and 3) relying on previous experience. Trading was the most common, used by everyone at least once, and often involved prioritizing key attributes over others, such as preferring a health state with significant depression because there is no pain. Reinterpretation was used by just under half (n=17) of participants and involved reconstructing health states by changing underlying assumptions. For example, rationalizing selecting a health state with significant pain because they could take pain medications and thus limit the pain. Lastly, some (n=13) relied on previous experience when making decisions. A participant with experience dealing with pain or depression, for instance, often prioritized health states with the least impact in these dimensions.

Conclusion

Evaluating the decision-making processes participants use in DCEs allows researchers to evaluate whether the tasks and attributes are interpreted accurately. The findings from this study add to the understanding of the generation of SF-6Dv2 health utility weights and threats to the validity of these weights. In particular, reinterpreting health states could undermine the validity of the DCEs and the derivation of utility weights. To mitigate this issue, we revised DCE instructions to make clear that all health states should be considered as written.