摘要:PURPOSE AND OBJECTIVES :Quality improvement (QI) coaching improves human papillomavirus (HPV) vaccination coverage, but effects of coaching have been small, and little is known about how and when QI coaching works. To assess implementation outcomes and explore factors that might explain variation in outcomes, we conducted a process evaluation of a QI coaching intervention for HPV vaccination. INTERVENTION APPROACH :QI coaches received tools and training to support 4 core coaching competencies: 1) expertise in using clinic-level adolescent vaccination data to drive change, 2) knowledge of the evidence base to support change in HPV vaccination practice, 3) familiarity with improvement strategies and action planning, and 4) skill in building relationships. EVALUATION METHODS :Our mixed methods evaluation involved collecting quantitative data through effort-tracking logs and gathering qualitative data through in-depth interviews with QI coaches (N = 11) who worked with 89 clinics in 3 US states. Data were collected on implementation outcomes and on contextual factors that might explain variations in those outcomes. Implementation outcomes included adoption by clinics, reach to providers and staff (ie, participation in the coaching visit), and implementation fidelity. RESULTS :States achieved either high adoption or high reach, but not both. For example, state A had high adoption with 94% of clinics accepting a coaching visit, but low reach with a median of 1 participant per clinic. In contrast, state C had lower adoption (29%, P < .01) than state A but higher reach (median of 4 participants per clinic, P < .01). Generally, states had high coaching protocol fidelity with the exception of advising on strategies and action planning. QI coaches described factors that might explain these variations, including strength of relationships with clinic staff and whether they recruited clinics directly or through large clinic networks. IMPLICATIONS FOR PUBLIC HEALTH :Our findings have implications for the design of future QI coaching initiatives, including how coaches recruit clinics to ensure full clinic engagement, refinements to coaching visits, and how QI coaches can effectively engage with clinic networks. Findings could inform future QI coaching interventions to strengthen their impact on public health.