Volume 51 | Number 6 | December 2016

Abstract List

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


To compare early and later adopters of the accountable care organization () model, using the taxonomy of larger, integrated system; smaller, physician‐led; and hybrid s.

Data sources

The National Survey of s, Waves 1 and 2.

Study design

Cluster analysis using the two‐step clustering approach, validated using discriminant analysis. Wave 2 data analyzed separately to assess differences from Wave 1 and then data pooled across waves.


Compared to early s, later adopter s included a greater breadth of provider group types and a greater proportion self‐reported as integrated delivery systems. When data from the two time periods were combined, a three‐cluster solution similar to the original cluster solution emerged. Of the 251 s, 31.1 percent were larger, integrated system s; 45.0 percent were smaller physician‐led s; and 23.9 percent were hybrid s—compared to 40.1 percent, 34.0 percent, and 25.9 percent from Wave 1 clusters, respectively.


While there are some differences between s formed prior to August 2012 and those formed in the following year, the three‐cluster taxonomy appears to best describe the types of s in existence as of July 2013. The updated taxonomy can be used by researchers, policy makers, and health care organizations to support evaluation and continued development of s.