Measuring (shared) decision-making--a review of psychometric instruments.

In recent years shared decision-making (SDM) has gained importance as an appropriate approach to patient-physician communication and decision-making. However, there is a conceptual variety that implies problems of inconsistent measurement, of defining relationships of SDM and outcome measures, and of comparisons across different studies. This article presents the results of a literature search of psychometric instruments measuring aspects of decision-making. Altogether 18 scales were found. The majority covers the patients' perspective and relates to preferences for information and participation, decisional conflict, self-efficacy as well as to the evaluation of decision-making process and outcomes. The scales differ widely in their extent of validation. Although this review is not exhaustive, it presents a variety of available decision-making instruments. Yet, many of them still need to show their psychometric quality for other settings in further studies.