The Medline/full-text research project.

This project was designed to test the relative efficacy of index terms and full-text for the retrieval of documents in those MEDLINE journals for which full-text searching was also available. The full-text files used were MEDIS from Mead Data Central and CCML from BRS Information Technologies. One hundred clinical medical topics were searched in these two files as well as the MEDLINE file to accumulate the necessary data. It was found that full-text identified significantly more relevant articles than did the indexed file, MEDLINE. The full-text searches, however, lacked the precision of searches done in the indexed file. Most relevant items missed in the full-text files, but identified in MEDLINE, were missed because the searcher failed to account for some aspect of natural language, used a logical or positional operator that was too restrictive, or included a concept which was implied, but not expressed in the natural language. Very few of the unique relevant full-text citations would have been retrieved by title or abstract alone. Finally, as of July, 1990 the more current issue of a journal was just as likely to appear in MEDLINE as in one of the full-text files.