Formal literature review and synthesis is an important component of Patient Outcomes Research Teams (PORTs) and the development of clinical practice guidelines supported by the Agency for Health Care Policy and Research (AHCPR). Investigators face unresolved methodological issues and practical problems in carrying out this work because the use of such systematic reviews is relatively new in medicine. In addition, standard meta-analytic methods may not readily be applied to the literature pertinent to most PORTs. Representatives of the InterPORT Work Group on Literature Review and Meta-Analysis exchanged information to identify and assess their respective approaches to these challenges. All 12 PORTs used systematic approaches to identifying relevant studies and to gather and analyze data abstracted from these studies. Most PORTs had undertaken or made plans for several separate reviews, which focused on a specific question about the outcomes of therapeutic health care services or procedures, diagnosis, prevention or prognosis. The descriptive information provided by PORTs reveals substantial commonalities in their methods for searching literature and organizing bibliographic databases. However, there was considerable variation in other aspects of reviews, such as selection/exclusion criteria, the use of blinding, and the techniques used to assess the quality of studies. Alternative approaches to literature review and synthesis warrant further examination because they have implications for research and health policy both in terms of the substantive conclusions and efficiency of reviews.