Hierarchical distributions and Bradford's Law

✍ Scribed by Basu, Aparna

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 780 KB
• Volume: 43
• Category: Article
• ISSN: 0002-8231
• DOI: 10.1002/(sici)1097-4571(199208)43:7<494::aid-asi4>3.0.co;2-f

✦ Synopsis

A probabilistic model of random fragmentation of the unit line provides the formal underpinning for deriving a distribution of the articles published in any field, over journals ranked in decreasing order of productivity. No assumptions need to be made about the causal mechanism that brings about such a distribution. Interestingly, the proportion of articles, p, that may be obtained from some given proportion, 9, of the most productive journals, is found to be greater than 9 by a factor -9 In 9. This may be interpreted as the additional "information" retrieved over the unranked case, and is a direct consequence of the procedure of ranking the journals. While the distribution obtained reproduces the general shape of a cumulative frequency log-rank graph of publications data, to ensure good fit to data, a parameter has to be introduced. This parameter may be considered to incorporate the effects of possible deviation from randomness, and is suggested as an indirect measure of concentration. 0 1992 John Wiley 81 Sons, Inc.

Bradford's Law

Bradford's "law" is the name given to an empirical relationship, first reported by S. C. Bradford (1934), Librarian, Science Museum Library, London, that describes the distribution of scholarly articles in any particular discipline in relevant journals. The law gained wide attention after the publication of Bradford's book, Documentation (Bradford, 1948).

Bradford found that a small core of journals publish the bulk of articles related to any particular discipline. By ranking the journals in decreasing order of "productivity," he was able to divide the articles into equal zones and show that the zones contained journals in the ratio of l:n:n'....