Methods: We conducted a systematic review of values clarification exercises, consulting electronic databases, reference lists, and expert contacts to identify articles describing the development, design and/or evaluation of exercises. We extracted data from included articles about decisions addressed, use of theory and guidelines, and development processes. We then developed a taxonomy of design features linked to relevant theories, used the taxonomy to catalogue exercises, and explored relationships between features. Finally, from articles reporting evaluations of exercises, we extracted data about heterogeneous outcomes, created a crude aggregate measure of overall effect, and explored associations between design features of exercises and overall effect.
Results: Out of 2145 articles eligible for screening, we identified 93 articles describing 81 values clarification exercises, of which 15 had been evaluated. Forty-one of 81 exercises (51%) addressed a decision between just two options. Most exercises (60%) were guided by neither theory nor guidelines. Development processes were described unevenly, with relatively little consultation with patients and infrequent reporting of methods that help make exercises easier for patients to use. The designs of exercises were extremely diverse. Only 56% of exercises were designed to be used independently by a patient. Most exercises (63%) were closed-ended, meaning that users could not add concerns that were not pre-specified in the exercise. Few exercises (11%) encouraged users to explore their values in an iterative discovery process. Users were presented with the implications of their stated values in 33% of exercises. Exploratory analyses suggested that exercises that showed users the implications of their expressed values were associated with positive overall effect (p = .006). Exercises based on relevant theory showed a trend toward overall positive effect (p = .06).
Conclusions: Values clarification exercises differ greatly in design. Many do not employ theories or guidelines. Many articles do not report development processes in detail. More research is needed to investigate the use of values clarification methods across decision contexts and to study the effects of different design features.