Volume 49 | Number 6 | December 2014

Abstract List

Stephen M. Shortell Ph.D., M.P.H., M.B.A., Frances M. Wu Ph.D., Valerie A. Lewis Ph.D., Carrie H. Colla Ph.D., Elliott S. Fisher M.D.


To develop an exploratory taxonomy of Accountable Care Organizations (s) to describe and understand early development and to provide a basis for technical assistance and future evaluation of performance.

Data Sources/Study Setting

Data from the National Survey of Accountable Care Organizations, fielded between October 2012 and May 2013, of 173 Medicare, Medicaid, and commercial payer s.

Study Design

Drawing on resource dependence and institutional theory, we develop measures of eight attributes of s 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.

Principal Findings

We identified a reliable and internally valid three‐cluster solution: that offer a broad scope of services and frequently include one or more postacute facilities; , centered in primary care, and that possess a relatively high degree of physician performance management; and that offer a moderately broad scope of services with some involvement of postacute facilities.


s 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.