Original Research Paper
Comparing the nine-item Shared Decision-Making Questionnaire to the OPTION Scale – an attempt to establish convergent validity
Version of Record online: 26 NOV 2012
© 2012 John Wiley & Sons Ltd
Volume 18, Issue 1, pages 137–150, February 2015
How to Cite
Scholl, I., Kriston, L., Dirmaier, J. and Härter, M. (2015), Comparing the nine-item Shared Decision-Making Questionnaire to the OPTION Scale – an attempt to establish convergent validity. Health Expectations, 18: 137–150. doi: 10.1111/hex.12022
- Issue online: 13 JAN 2015
- Version of Record online: 26 NOV 2012
- Manuscript Accepted: 10 OCT 2012
- convergent validity;
- shared decision-making
While there has been a clear move towards shared decision-making (SDM) in the last few years, the measurement of SDM-related constructs remains challenging. There has been a call for further psychometric testing of known scales, especially regarding validity aspects.
To test convergent validity of the nine-item Shared Decision-Making Questionnaire (SDM-Q-9) by comparing it to the OPTION Scale.
Setting and participants
Data were collected in outpatient care practices. Patients suffering from chronic diseases and facing a medical decision were included in the study.
Consultations were evaluated using the OPTION Scale. Patients completed the SDM-Q-9 after the consultation. First, the internal consistency of both scales and the inter-rater reliability of the OPTION Scale were calculated. To analyse the convergent validity of the SDM-Q-9, correlation between the patient (SDM-Q-9) and expert ratings (OPTION Scale) was calculated.
A total of 21 physicians provided analysable data of consultations with 63 patients. Analyses revealed good internal consistency of the SDM-Q-9 and limited internal consistency of the OPTION Scale. Inter-rater reliability of the latter was less than optimal. Association between the total scores of both instruments was weak with a Spearman correlation of r = 0.19 and did not reach statistical significance.
By the use of the OPTION Scale convergent validity of the SDM-Q-9 could not be established. Several possible explanations for this result are discussed.
This study shows that the measurement of SDM remains challenging.