title: A taxonomy of accountable care organizations for policy and practice.
abstract: OBJECTIVE
  To develop an exploratory taxonomy of Accountable Care Organizations (ACOs) to describe and understand early ACO development and to provide a basis for technical assistance and future evaluation of performance.
  
  
  METHODS
  Data from the National Survey of Accountable Care Organizations, fielded between October 2012 and May 2013, of 173 Medicare, Medicaid, and commercial payer ACOs.
  
  
  METHODS
  Drawing on resource dependence and institutional theory, we develop measures of eight attributes of ACOs such as size, scope of services offered, and the use of performance accountability mechanisms. Data are analyzed using a two-step cluster analysis approach that accounts for both continuous and categorical data.
  
  
  RESULTS
  We identified a reliable and internally valid three-cluster solution: larger, integrated systems that offer a broad scope of services and frequently include one or more postacute facilities; smaller, physician-led practices, centered in primary care, and that possess a relatively high degree of physician performance management; and moderately sized, joint hospital-physician and coalition-led groups that offer a moderately broad scope of services with some involvement of postacute facilities.
  
  
  CONCLUSIONS
  ACOs can be characterized into three distinct clusters. The taxonomy provides a framework for assessing performance, for targeting technical assistance, and for diagnosing potential antitrust violations.
authors.affiliation: School of Public Health, University of California, Berkeley, Berkeley, CA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Shortell
authors.forename: Frances M
authors.initials: FM
authors.lastname: Wu
authors.forename: Valerie A
authors.initials: VA
authors.lastname: Lewis
authors.forename: Carrie H
authors.initials: CH
authors.lastname: Colla
authors.forename: Elliott S
authors.initials: ES
authors.lastname: Fisher
mesh_terms: D060866:Accountable Care Organizations / Q000145:classification* / Q000458:organization & administration / Q000592:standards*; D006801:Humans; D057766:Policy; D014481:United States
keywords: Accountable care organizations; Medicare; delivery of health care; health care reform; health policy; incentives in health care