Researchers within health maintenance organizations (HMOs) need to cre
ate greater opportunities for collaborative research within their orga
nizations. Multisite research will yield high-quality information for
improving care. This paper describes situations in which competition a
s well as collaboration are possible across HMOs in the current enviro
nment. The paper considers the following questions: (1) What criteria
determine if a project can be conducted as a multisite study; and (2)
what population and organizational features should be considered when
designing cross-site collaboration? The paper also discusses two impor
tant trends in the larger health care environment: cost containment, w
hich is both a challenge and an opportunity for health services resear
chers working within managed care; and mergers and acquisitions, which
are changing the face of the larger health care industry.