Planning for effective use of on-line systems

A perspective of developments in the field of computerized information retrieval is presented, and policies are suggested for the efficient use of on-line systems. Examples of MEDLINE, CHEMCON, AND TOXLINE searches are given with cost data and compared, where possible, with manual searches. The lowest costs were obtained with on-line searching by information scientists. MEDLINE is superior in quality to manual searching of Index Medicus, but on-line searching of Chemical Abstracts keywords is not an effective substitute for manual searching of Chemical Abstracts Substance Indexes.