Population-based insurance systems using longitudinal administrative data and record linkage techniques have helped create "information-rich" environments in several sites around the world. The output of five research groups using administrative data (Oxford, Western Australia, and three Canadian centres: Manitoba, Ontario and British Columbia) was analysed from contacts with the research groups and through use of the National Library of Medicine's PubMed and Medical Subject Headings (MeSH) categories. MeSH words "utilization", "economics", "physicians", and "physician practice patterns" more frequently characterized the research by the three Canadian centres than that of the other sites. With core funding for deliverables negotiated with the provincial health ministries, Canadian researchers have been more likely to use linked databases for policy analyses. Manitoba examples highlight the capabilities associated with these information-rich environments. They include the ability to analyse interventions longitudinally; to compare regions, areas and hospitals in defined populations; to combine information on patients and physicians; to add up expenditures for different services within the Canadian health-care system; and to examine population health issues in areas such as education and family services. Well-organized data and the capability for rapid response have been critical for timely policy analysis in Manitoba. A number of successes are mentioned; less successful efforts to influence practice patterns and to modify the internal workings of hospitals are noted. Investments in filling gaps in data collection and in enriching existing data would facilitate additional research. Planning and managing health care for an entire population has benefited greatly from the development of an information-rich environment.