This project examined the impact of the University of Texas Health Science Center's Circuit Library Health Information Network (CLHIN) on availability and usage of medical information to health professionals and the effect of the promotion of online services, GRATEFUL MED and MEDLINE (flat rate). The project included a survey of physicians, analysis of use statistics of CLHIN services, and analysis of flat-rate password purchasers and use. Findings showed that differences in user profiles did not affect information usage; differences in information use between physicians in urban and rural areas are related to the use of MEDLINE and libraries; physicians did not search MEDLINE by themselves; the program has succeeded in providing information to an underserved area; CLHIN's impact in developing GRATEFUL MED users is not measurable; the generalizability of the CLHIN model of circuit librarianship is unclear; an effective circuit librarian and institutional liaison are critical to success; the project was successful in introducing users to online services; perceived value for price and convenience motivated purchase of the flat-rate password; the median reasonable flat-rate charge recommended by participants was $150; use of the flat-rate password varied by professional training and academic affiliation. Also included are 37 statistical tables, a report on medical information and availability, physician information needs surveys, a description of promotional and training activities, and a survey of flat-rate MEDLINE password holders. (Contains 39 references.) (KRN)