The Key Driver Implementation Scale (KDIS) for practice facilitators: Psychometric testing in the “Southeastern collaboration to improve blood pressure control” trial

BACKGROUND: Practice facilitators (PFs) provide tailored support to primary care practices to improve the quality of care delivery. Often used by PFs, the “Key Driver Implementation Scale” (KDIS) measures the degree to which a practice implements quality improvement activities from the Chronic Care Model, but the scale’s psychometric properties have not been investigated. We examined construct validity, reliability, floor and ceiling effects, and a longitudinal trend test of the KDIS items in the Southeastern Collaboration to Improve Blood Pressure Control trial. METHODS: The KDIS items assess a practice’s progress toward implementing: a clinical information system (using their own data to drive change); standardized care processes; optimized team care; patient self-management support; and leadership support. We assessed construct validity and estimated reliability with a multilevel confirmatory factor analysis (CFA). A trend test examined whether the KDIS items increased over time and estimated the expected number of months needed to move a practice to the highest response options. RESULTS: PFs completed monthly KDIS ratings over 12 months for 32 primary care practices, yielding a total of 384 observations. Data was fitted to a unidimensional CFA model; however, parameter fit was modest and could be improved. Reliability was 0.70. Practices started scoring at the highest levels beginning in month 5, indicating low variability. The KDIS items did show an upward trend over 12 months (all p < .001), indicating that practices were increasingly implementing key activities. The expected time to move a practice to the highest response category was 9.1 months for standardized care processes, 10.2 for clinical information system, 12.6 for self-management support, 13.1 for leadership, and 14.3 months for optimized team care. CONCLUSIONS: The KDIS items showed acceptable reliability, but work is needed in larger sample sizes to determine if two or more groups of implementation activities are being measured rather than one.