What Was Measured?

The number of enrollees in commercial, MediCal, and Medicare HMO product lines offered by California’s largest HMOs. HMO membership by type of insurance is not ranked because it is not a quality measure.

Why Is It Important?

Enrollees may feel more comfortable in one HMO than another depending on the range of covered services, the perceived stability of the HMO, or the availability of different types of physicians who best meet their needs. The number of enrollees in an HMO’s commercial, MediCal, and Medicare product lines is one indication of how Californians select their HMO.

What Was the Source?

Data voluntarily reported by California HMOs to the National Committee for Quality Assurance (NCQA) and made available through NCQA’s Quality Compass®. The HMO Membership by Type of Insurance data comes from NCQA’s 2011 Quality Compass®, and is part of the same HMO data set used to generate the HEDIS and CAHPS quality information found in the health plan section of the 2012 OPA Report Card.

HMO Members by Type of Insurance

Aetna data for Medi-Cal and Medicare from 2010 reported directly to OPA

HMO Commercial

HMO Medi-Cal

HMO Medicare

Aetna Health of California, Inc. 380,414  Not reported 24,452 
Anthem Blue Cross - HMO 2,290,428  1,557,481  170,908 
Blue Shield of California - HMO 882,779  52,882 
CIGNA HMO 195,677 
Health Net of California, Inc. 767,321  907,694  132,881 
Kaiser Permanente - Northern California 2,492,423  80,788  417,332 
Kaiser Permanente - Southern California 2,605,747  92,096  384,802 
UnitedHealthcare of California (formerly PacifiCare) 575,656  305,810 
Western Health Advantage 79,719