Original ArticlesEstablishing Teams How Does It Change Practice Configuration, Size, and Composition?Chien, Alyna T. MD, MS; Kyle, Michael Anne MS; Peters, Antoinette S. PhD; Nguyen, Kevin H. MS; Tendulkar, Shalini A. ScD, ScM; Ryan, Molly MPH; Hacker, Karen MD, MPH; Singer, Sara J. PhD, MBA Author Information Department of Pediatrics, Harvard Medical School, and Division of General Pediatrics, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts (Dr Chien); Harvard Business School, Boston, Massachusetts (Ms Kyle); Department of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, Massachusetts (Ms Kyle and Mr Nguyen); Department of Population Medicine, Harvard Pilgrim Health Care Institute, and Harvard Medical School, Boston, Massachusetts (Dr Peters); Institute for Community Health, Malden, and Department for Community Health, Tufts University, Medford, Massachusetts (Dr Tendulkar); Harbor Health Services Inc, Dorchester, Massachusetts (Ms Ryan); Allegheny County Health Department, Pittsburgh, Pennsylvania (Dr Hacker); and Department of Medicine, Stanford School of Medicine, California (Dr Singer). Correspondence: Alyna T. Chien, MD, MS, Division of General Pediatrics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115 ([email protected]). We thank Meredith Rosenthal, PhD, for her contributions as a core member of the evaluation team, as well as Eileen Dryden, PhD, Diana Eastman, BA, and Julia Martin, MS, for their contributions to data collection and initial analyses.The Center for Primary Care at Harvard Medical School and the Controlled Risk Insurance Company Risk Management Foundation funded this study.The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article.Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.ambulatorycaremanagement.com). Journal of Ambulatory Care Management 41(2):p 146-155, April/June 2018. | DOI: 10.1097/JAC.0000000000000229 Buy SDC Metrics Abstract Little is known about how practices reorganize when transitioning from traditional practice organization to team-based care. We compared practice-level (1) configuration as well as practice- and team-level (2) size and (3) composition, before and after establishing teams. We employed a pre-/poststudy using personnel lists of 1571 to 1711 staff (eg, job licenses, titles, and team assignment) and practice manager surveys. All personnel (physician and nonphysician) worked within 18 Massachusetts academic primary care practices participating in a 2-year learning collaborative aimed at establishing team-based care. We found that establishing team-based care can involve changing practice configurations and composition without substantially changing practice size. © 2018 Wolters Kluwer Health, Inc. All rights reserved.