Library and Information Science

In her previous article, the writer discussed MEDLARS indexing policies and practices as reflected in the evaluation project conducted by F. W. Lancaster and his group at the National Library of Medicine of the United States. The present paper is concerned primarily with the MEDLARS searching, another intellectual factors which significantly affect the performance of an information retrieval system. Searching for the MEDLARS demand search services largely depends upon intellectual efforts of human searchers; analysis of search requests, translation of the contents into the appropriate terms of the system’s controlled vocabulary, and preparation of search formulations in pertinent logical equation are all practised by a group of searchers. With her own experience in MEDLARS searching at the National Library of Medicine, the writer discusses MEDLARS searching as seen through the eyes of Lancaster in his evaluation project. An observation is also given of the MEDLARS index language, Medical Subject Headings, since it seems meaningless to discuss of indexing and searching without the vocabulary on which the entire system is based.