Bradford's law

Bradford's law examines the frequency of relevant journal articles in groups of journals. It assumes that journals are ranked by relevance and that the frequency of relevant articles is given by a negative power law.

Suppose that in a month there are 12 articles of interest in those journals. Suppose further that in order to find another dozen articles of interest, the researcher would have to go to an additional 10 journals. Then that researcher's Bradford multiplier bm is 2 (ie 10/5). For each new dozen articles, that researcher will need to look in bm times as many journals. After looking in 5, 10, 20, 40, ... journals, most researchers quickly realize that there is little point in looking further.

The parameters of the distribution will differ for different researchers and/or fields, and presumably vary over time.

It would be interesting to explore the implications of this observed relationship for knowledge systems in developing nations. One wonders, for example, how good page rank algorithms and their like are in ordering sources for relevance.