Completing the third person's perspective on patients' involvement in medical decision-making: approaching the full...

Shared decision making is based on the idea of cooperation and partnership between patients and doctors. In this concept both parties may initiate and perform specific decision-making steps. However, the common observation-based instruments focus solely on doctors' behaviour. Content and quality of information provided to involve patients in medical decisions are hardly considered in evaluation of SDM. This study investigates the advantages of a revised observer inventory taking into account these aspects.

Based on the OPTION scale, a more comprehensive observation-based inventory was developed, additionally considering both the patient-sided indicators for patient involvement and the criteria of evidence-based patient information. The inventory comprises three scales (doctor, patient, doctor-patient dyad) and 15 indicators each. Rater training and re-analyses of 76 consultations previously analysed using the OPTION scale were conducted. Convergent validities were calculated between the observer-based scales and the patients' ratings on the Shared Decision Making Questionnaire, the Decisional Conflict Scale and the Control Preference Scale.

Interrater reliabilities of the revised scales were high (r=.87 to .74) and even higher when only the dyadic perspective was coded (.86). The revised inventory provided additional information on the involvement taking place. No substantive correlations were found between observation-based and patients' subjective judgments.

The observers' perspective on patient involvement needs to consider patient activities. Inconsistencies of patients' and observers' judgements concerning patient participation need further investigation.