This study evaluated online searching performed on the National Library of Medicine system to identify implications for training and continuing education. Searchers were selected with formal and informal training, from three different types of organization, and with differing levels of experience. It was found that most searchers have clearly mastered the basics of searching, and that performance was unaffected by source of training, experience, organizational, or even subject educational background. The most consistent source of difference in performance was the difficulty of the search itself. It becomes necessary to determine characteristics of search requests to determine what makes a search easy or difficult, and to identify inherent limitations in databases and retrieval systems that hinder searching. The study concludes that searching is a highly individualized process, that there are good and bad searching practices, that training programs need revision to identify and illustrate workable search techniques, and that the user community needs to debate the issues of search techniques. (RAA)