Deutsch | Imprint


Zoom = Maus über Bild bewegen | Bild hier öffnen


Final report PEF-FB Scholl (German)



Principal investigator
Prof. Dr. Dr. Martin Härter / Dr. Jörg Dirmaier


Isabelle Scholl, Dipl. Psych.
Universitätsklinikum Hamburg-Eppendorf (UKE)
Institut und Poliklinik für Medizinische Psychologie
Martinistr. 52
20246 Hamburg
Tel.: 040/7410 57135

previous article  |  next article

“Validation and normative values of the 9-item Shared Decision Making Questionnaire (SDM-Q-9)”

Background and aims

The 9-item Shared Decision Making Questionnaire measures patients’ participation in medical decisions from the patients’ perspective. The revised version (SDM-Q-9) shows a good reliability, a one-factor structure as well as good acceptance. The aim of this project was to test the convergent validity of the SDM-Q-9 by comparing it to an observer rating (OPTION scale) of medical consultations and subsequently the calculation of normative values of the scale for three different conditions (type 2 diabetes, chronic back pain, depression). We expected a medium-sized correlation between the SDM-Q-9 and the OPTION scale. In the first project phase it became apparent that to date, there is no psychometrically tested instrument which assesses the process of shared decision making from the physicians’ perspective. This led to a further project aim, which consisted of adapting the existing version of the SDM-Q-9 to a physician version (SDM-Q-Doc) and to test its reliability and factorial validity.



Data were collected in a primary and secondary outpatient care sample in Hamburg. The aim was to recruit 30 physicians to participate in the study, who for their part should each include 13 patients with the above-mentioned diagnoses. Following the consultation, the patients and physicians filled out the SDM-Q-9 or the SDM-Q-Doc, respectively. Moreover, part of the consultations was audio-taped, transcribed and evaluated by two trained raters using the OPTION scale. The primary analyses consisted of the determination of Spearman’s Rho correlation between the total scores of the SDM-Q-9 and the OPTION scale. Normative values were presented as percentiles. To test the psychometric properties of the SDM-Q-Doc, the internal consistency, descriptive statistics as well as a confirmatory factor analysis were calculated.



In total, N=29 physicians were recruited to participate in the study, who in turn included N=324 patients, N=63 of whom had analysable audio recordings. The association between the sum scores of the two instruments was weak, with a Spearman correlation of r=.19 and just failed to reach statistical significance (P=.069). Normative values for the total sample (N=301) were compiled. Moreover, separate normative value tables for patients with different educational levels were created, as these differed significantly in terms of distribution. The SDM-Q-Doc showed a good acceptance by the physicians. The calculation of internal consistency resulted in a Cronbach’s α of 0.88. The confirmatory factor analysis confirmed the one-dimensional structure of the construct.



The hypothesis of a medium-sized relationship between the SDM-Q-9 and the OPTION scale could not be confirmed. Possibly, the low correlation can be partly attributed to the low variance due to ceiling effects of the SDM-Q-9 and floor effects of the OPTION scale. Current studies in the area of patient participation and physician-patient communication show similarly divergent perspectives of patients and experts. On the whole, the SDM-Q-Doc shows good psychometric properties and enables the perspectives of physician and patient on the decision-making process to be compared in further studies.




Cooperation partners at the Universtiy Medical Center Hamburg


National and international cooperation partners

< PrefCheck - Junius-Walker  |  PoInts - Grande >