MEDICAL SUBJECT HEADINGS IN MEDLARS.

Use of an identical subject heading list for both machine searching and publication creates problems. Necessary compromises include precoordination of some headings for publication and use of some coordinates in the computer system that are not appropriate for a printed index. Determination of the headings under which a citation will appear in Index Medicus and those which will be used for it only in the computer requires anticipation of the way the published index will be used for search. Methods of selecting new terms are discussed and opinions solicited. The computer will be used in several ways to update the system and provide for annual publication of the subject heading list.