Library and Information Science

As secondary services and publications are becoming multiform, any single measure of evaluation, such as time-lag or coverage, cannot meet diversifying requirements of present-day users. For retrospective search they must be as informative as possible, thoroughly indexed, with comprehensive coverage, although at the sacrifice of up-to-dateness. On the contrary, current-awareness services should be concise, clearly for matted, selective according to importance, and prompt.

For example the Japan Information Center's (JICST) Bunken Sokuho much meets the criteria for current-awareness service rather than those for retrospective search, as compared with the Chemical Abstracts.

When the time-lag and amount of imformation (in terms of number of lines per abstract) are taken as coordinates, the fitness for current-awareness or retrospective search is graphically shown. Samples were taken from various abstracting/indexing journals.