Importance: Primary care panel size plays an increasing role in measuring primary care provider (ie, physicians and advanced practice providers, which include nurse practitioners and physician assistants) workload, setting practice capacity, and determining pay and can influence quality of care, access, and burnout. However, reported panel sizes vary widely.
Objective: To identify how panels are defined, the degree of variation in these definitions, the consequences of different definitions of panel size, and research on strengths of different approaches.
Evidence review: Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, MEDLINE, Web of Science, Embase, and Dissertations and Theses Global databases were searched from inception to April 28, 2021, for subject headings and text words to capture concepts of primary care panel size. Article review and data abstraction were performed independently by 2 reviewers. Main outcomes reported included rules for adding or removing patients from panels, rules for measuring primary care provider resources, consequences of different rules on reported panel size, and research on advantages and disadvantages of different rules.
Findings: The literature search yielded 1687 articles, with 294 potentially relevant articles and 74 containing relevant data. Specific practices were identified from 29 health care systems and 5 empanelment implementation guides. Patients were most commonly empaneled after 1 primary care visit (24 of 34 [70.6%]), but some were empaneled only after several visits (5 [14.8%]), enrollment in a health plan (4 [11.8%]) or any visit to the health care system (1 [3.0%]). Patients were removed when no visit had occurred in a specified look-back period, which varied from 12 to 42 months. Regarding primary care provider resources, half of organizations assigned advanced practice providers independent panels and half had them share panels with a physician, increasing the physician's panel by 50% to 100%. Analyses demonstrated that changes in individual rules for adding patients, removing patients, or estimating primary care provider resources could increase reported panel size from 20% to 100%, without change in actual primary care provider workload. No research was found investigating advantages of different definitions.
Conclusions and relevance: Much variation exists in how panels are defined, and this variation can have substantial consequences on reported panel size. Research is needed on how to define primary care panels to best identify active patients, which could contribute to a widely accepted standard approach to panel definition.