THE USE OF SCIENTIFIC LITERATURE AT THE SCIENCE REFERENCE LIBRARY FOR UPDATING SEARCHES

The use per issue‐day of recent issues of 125 periodicals on open access at the Science Reference Library (SRL) has been studied for over four months. There is statistical evidence for the expected separate phase within ‘updating’ of ‘current awareness scanning’ of issues which have arrived since the reader's last visit to the library: its half‐life of two to three months reflects the pattern of reader‐visit frequencies rather than any characteristics of the literature. The isolated uses of issues of periodicals, representing a part of ‘following up searches’, showed no significant relation between use and age. The irregular monographic and conference series, with their unpredictable dates of arrival at the shelf, were not subject to current awareness scanning. Of the regular periodicals in the two chemical technologies, ‘magazines’ were more heavily used than ‘journals’ and, as expected, issues in the English language more heavily than those in foreign languages: these differences were less marked in chemical sciences than in chemical technologies. The results include figures for the variances of use data. These were so high as to suggest that lists of periodical titles ranked by use per issue data are of very little value in critical decisions between one little used title and another. Differences in rank, resulting from a difference of less than fifteen uses obtained from less than five monthly surveys, are unlikely to be significant. Ranking by use per title instead of by use per issue (or equivalent) tends to arrange journals in size order.