Determining the impact of health library services on patient care: a review of the literature.

The impact of health library information has been studied in a number of settings and populations. This review examines both the methods employed and the outcomes reported in a series of impact studies conducted in four countries since the late 1980's. It demonstrates that health library information can affect patient care outcomes in various ways and has high cognitive and clinical value in diagnosing and treating patients. But there remains no agreed technique or methodology for determining the level of this impact. In many cases evaluation of the health library's impact will be located within a central process of evaluation of the greater organization to which the library belongs. Consequently, local ad hoc evaluation is rarely reported outside an organization. The author considers the question of whether it is worthwhile doing an impact study and what form it might take. The author concludes by identifying seminal papers on the topic.