Comprehensiveness and Timeliness

The SCl’s method of obtaining comprehensive coverage of the literature has its foundation in Bradford’s Law (16.17). In general, this law states that a small percentage of journals account for a large percentage of the signiEcant articles in any given field of science. In support of this, a study of Physics Abstracts by Keenan and Atherton (18) shows that 50% of the items abstracted are taken from only nmeteen journals. Also, studies conducted by index Chemicus show that 100 journals account for 98% of all new articles in synthetic chemistry (19). Further analyses have revealed that thts concentration of information in relatively few journals is characteristic, not only of the individual disciplines, but of the scientific literature as a whole. Yale Professor Derek J. de Solla Price claims that about 1000 journals contain 80% of all scientific articles (20). This estimate is confirmed by continuing IS/ studies. These same studies show that fewer than 1000 journals account for 90% of the significu~f literature, that is, they are the most heavily cited journals (21). These findings lead to the reasoning that if the 2200 journals covered by the SC1 are properly chosen, most of the world’s important scientific literature will