Background - The 16-item Decisional Conflict Scale (DCS) with 5 response categories has been shown to be an effective research tool to evaluate decision aids and tailor decision support interventions for patients. A simpler DCS format using 10 items with 3 response categories was developed to monitor the implementation of shared decision making in a clinical setting.

Purpose - To evaluate the psychometric properties of this 10-item Decisional Conflict Scale.

Methods - 130 newly-diagnosed breast cancer patients completed a computerized intake questionnaire for breast cancer. This tool captures, summarizes, and reports patients' clinical and decision-making data, including their decisional conflict. Then patients watched a video-based decision aid (“Early Stage Breast Cancer: Choosing Your Surgery”) that provides information about early stage invasive breast cancer and the surgery treatment choices. Patients responded to the 10-item DCS again after the video, and again after the surgical consultation. Data about treatment intention and actual surgery choice were also collected.

Results - The 10-item DCS's internal consistency coefficients (alpha) ranged from 0.85 to 0.73. The scale discriminated significantly (p < .0001) between those who were uncertain and those with intentions for a particular surgical treatment. Patients with higher decisional conflict were more likely to change their minds about surgical treatment (OR = 4.0, 95% CL 1.8 – 9.3). Subscale scores indicating problems with knowledge and with unclear values were significantly lower after the video intervention (p < .0001); subscale scores for problems with support and uncertainty were significantly lower after consultation with the surgeon (p < .0001); and total decisional conflict scores were significantly lower both after the video and after meeting the physician (p < .0001).

Conclusions - The 10-item Decisional Conflict Scale's psychometric properties fall within acceptable limits. Among newly diagnosed breast cancer patients, the scale's new item/response format is able to evaluate the impact of a decision aid, identify support needs, and respond to changes over time. Further validation of the 10-item scale in other healthcare decisions is warranted.