Of the two main types of health maintenance organizations (HMOs), IPA/netwo
rk HMOs (which contract with independent practice associations (IPAs) and o
ther medical groups) have grown faster than group/staff HMOs (which partner
with exclusive multispecialty medical groups or employ staff physicians).
However, because the IPA/network HMOs in California contract with wide and
overlapping networks of physicians and hospitals in order to satisfy purcha
ser demand, these arrangements suffer from inefficiencies that confound and
frustrate physicians and consumers and these arrangements fail to provide
the highest-quality most-economic care. This article reviews the historical
context and growth of managed care in California and then delineates effic
iency problems due to overlapping networks of IPA/network HMOs. The authors
also review a variety of potential strategies for addressing these problem
s and discuss advantages and disadvantages of each option.