Observations of end-user online searching behavior over eleven years.

End-user searching of National Library of Medicine (NLM) online data bases during eleven years has been investigated through transaction logs, questionnaires, and follow-up interviews. From 1976 through 1984, pathologists and pharmacists performed 8,313 searches. Highlights of our studies are compared with a review of other end-user research. Volume of searching is directly related to the convenient placement of the terminal in the work place. Slightly fewer than half of all potential searchers actually search for themselves. Practices of pharmacists and pathologists do not differ in important ways. Nonmediated searchers feel they need answers more promptly than do those who obtain mediated searches. End-users perform very simple searches, mostly using only the AND operator. Problems with techniques are fewer and more easily solved than those with the vocabulary and content of the system. The major problems, with the most powerful capabilities of MEDLINE--subheadings and explosions--sometimes cause substantial loss of references, but in relatively few searches. One-on-one teaching is most popular, with trial-and-error the most frequent procedure used in actual learning.