(definition)

**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 <uk_arvind@mail.utexas.edu> 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], Vreda Pieterse and Paul E. Black, eds. 17 December 2004. (accessed TODAY)
Available from: http://www.nist.gov/dads/HTML/bradfordsLaw.html