We searched the databases PubMed, SSRN, EconLit, Sociological Abstracts, Business Practices and Management, and Conference Proceedings for articles published between January 1, 1985 and December 31, 2007. Search terms included episode AND payment OR reimbursement OR performance OR quality; bundl* AND payment OR reimbursement OR performance OR quality; episode AND attribution; bundl* AND attribution; virtual AND provider AND network; accountable AND organization AND payment OR quality; assign* AND responsibility AND physician OR provider; "physician-hospital organization"; "medical home"; "primary care" AND pay* AND responsibility. We added additional references from a previously conducted systematic review of health care efficiency measures, which use episodes of care as the unit of measurement (McGlynn et al., 2008). - We also searched the gray literature for related publications by organizations including CMS, the Medicare Payment Advisory Commission (MedPAC), the Commonwealth Fund, the NQF, and the Leapfrog Group. We performed reference mining by searching the bibliographies of retrieved publications for additional relevant publications.