A systematic review of assessment instruments used in studies on shared decision making

Shared decision making (SDM) is a model of communication processes that facilitate cooperative decision making between a patient and medical practitioner regarding treatment. The use of assessment instruments is an important way to gain insight into the practice of SDM. In order to fully utilize the various assessment tools available for use, it is important to not only reveal what instruments are used to measure SDM but also shed light on which aspects of SDM are captured by different instruments. However, the instruments currently used to measure SDM are unclear, as are the aspects of SDM processes each instrument reflects. So that, we reviewed assessment instruments used in studies on SDM with the aim of clarifying what aspects of SDM processes each instrument was intended to capture in this study. As a result, we identified 16 assessment instruments used in 115 articles concerning SDM as the main theme. The most commonly used instrument was the OPTION scale, followed by SDM-Q-9. Step 4 (“informing on the benefits and risks of the options”) was covered by most instruments, followed by Step 5 (“investigation of the patient’s understanding and expectations”). In the future, assessment instruments for SDM will likely be used primarily in areas in which there is considerable uncertainty about evidence, and where multiple options exist. When you assess SDM, it is necessary to be able to select the evaluation indicator that suits the purpose.