Bradford's law


Definition: Journals in a field can be divided into three parts, each with about one-third of all articles: 1) a core of a few journals, 2) a second zone, with more journals, and 3) a third zone, with the bulk of journals. The number of journals is 1:n:n².

See also Lotka's law.

Note: Bradford formulated his law after studying a bibliography of geophysics, covering 326 journals in the field. He discovered that 9 journals contained 429 articles, 59 contained 499 articles, and 258 contained 404 articles. Although Bradford's Law is not statistically accurate, librarians commonly use it as a guideline.

Contributed by Arvind <> May 2002.

Author: PEB

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Entry modified 17 December 2004.
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Cite this as:
Paul E. Black, "Bradford's law", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 17 December 2004. (accessed TODAY) Available from: