Bradford's law is a pattern first described by Samuel C. Bradford in 1934 that estimates the exponentiallydiminishing returns of searching for references in science journals. One formulation is that if journals in a field are sorted by number of articles into three groups, each with about one-third of all articles, then the number of journals in each group will be proportional to 1:n:n².[1] There are a number of related formulations of the principle.
In many disciplines, this pattern is called a Pareto distribution. As a practical example, suppose that a researcher has five core scientific journals for his or her subject. 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 (i.e. 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, etc. journals, most researchers quickly realize that there is little point in looking further.
Different researchers have different numbers of core journals, and different Bradford multipliers. But the pattern holds quite well across many subjects, and may well be a general pattern for human interactions in social systems. Like Zipf's law, to which it is related, we do not have a good explanation for why it works, but knowing that it does is very useful for librarians. What it means is that for each specialty, it is sufficient to identify the "core publications" for that field and only stock those; very rarely will researchers need to go outside that set.
However, its impact has been far greater than that. Armed with this idea and inspired by Vannevar Bush's famous article As We May Think, Eugene Garfield at the Institute for Scientific Information in the 1960s developed a comprehensive index of how scientific thinking propagates. His Science Citation Index (SCI) had the effect of making it easy to identify exactly which scientists did science that had an impact, and which journals that science appeared in. It also caused the discovery, which some did not expect, that a few journals, such as Nature and Science, were core for all of hard science. The same pattern does not happen with the humanities or the social sciences.
The result of this is pressure on scientists to publish in the best journals, and pressure on universities to ensure access to that core set of journals. On the other hand, the set of "core journals" may vary more or less strongly with the individual researchers, and even more strongly along schools-of-thought divides. There is also a danger of over-representing majority views if journals are selected in this fashion.
Bradford's law is also known as Bradford's law of scattering or the Bradford distribution, as it describes how the articles on a particular subject are scattered throughout the mass of periodicals.[2] Another more general term that has come into use since 2006 is information scattering, an often observed phenomenon related to information collections where there are a few sources that have many items of relevant information about a topic, while most sources have only a few.[3] This law of distribution in bibliometrics can be applied to the World Wide Web as well.[4]
Hjørland and Nicolaisen (2005, p. 103) identified three kinds of scattering:
Lexical scattering. The scattering of words in texts and in collections of texts.
Semantic scattering. The scattering of concepts in texts and in collections of texts.
Subject scattering. The scattering of items useful to a given task or problem.
They found that the literature of Bradford's law (including Bradford's own papers) is unclear in relation to which kind of scattering is actually being measured.
Law's interpretationsEdit
The interpretation of Bradford's law in terms of a geometric progression was suggested by V. Yatsko,[5] who introduced an additional constant and demonstrated that Bradford distribution can be applied to a variety of objects, not only to distribution of articles or citations across journals. V. Yatsko's interpretation (Y-interpretation) can be effectively used to compute threshold values in case it is necessary to distinguish subsets within a set of objects (successful/unsuccessful applicants, developed/underdeveloped regions, etc.).
Related laws and distributionsEdit
Benford's law, originally used to explain apparently non-uniform sampling
Lotka's law, describes the frequency of publication by authors in any given field.
Power law, a general mathematical form for "heavy-tailed" distributions, with a polynomial density function. In this form, these laws may all be expressed and estimates derived.
^VICKERY, B.C. (1948-01-01). "Bradford's Law of Scattering". Journal of Documentation. 4 (3): 198–203. doi:10.1108/eb026133. ISSN 0022-0418.
^"Information Scattering". Encyclopedia of Library and Information Sciences, Third Edition. CRC Press. 2009-12-17. pp. 2564–2569. doi:10.1081/E-ELIS3-120043255. ISBN978-0-203-75763-5.
^Turnbull, Don (1997). . University of Toronto Technical Report. Archived from the original on 2007-04-02. Retrieved 2007-07-05. {{cite journal}}: Cite journal requires |journal= (help)
^Yatsko, V. A. (2012). "The interpretation of Bradford's law in terms of geometric progression". Automatic Documentation and Mathematical Linguistics. 46 (2): 112–117. doi:10.3103/S0005105512020094. S2CID 255432905.
Bradford, Samuel C., Sources of Information on Specific Subjects, Engineering: An Illustrated Weekly Journal (London), 137, 1934 (26 January), pp. 85–86.
Reprinted as:
Bradford, Samuel C. Sources of information on specific subjects, Journal of Information Science, 10:4, 1985 (October), pp. 173–180 [1]
Hjørland, Birger; and Nicolaisen, Jeppe (2005), Bradford's law of scattering: ambiguities in the concept of "subject", in Proceedings of the 5th International Conference on Conceptions of Library and Information Science: 96–106.
Nicolaisen, Jeppe; and Hjørland, Birger (2007), Practical potentials of Bradford's law: A critical examination of the received view, Journal of Documentation, 63(3): 359–377. Available and here
Suresh K. Bhavnani, Concepcio´n S. Wilson, Information Scattering. Available [2]
External linksEdit
August 27, 2023
bradford, pattern, first, described, samuel, bradford, 1934, that, estimates, exponentially, diminishing, returns, searching, references, science, journals, formulation, that, journals, field, sorted, number, articles, into, three, groups, each, with, about, t. Bradford s law is a pattern first described by Samuel C Bradford in 1934 that estimates the exponentially diminishing returns of searching for references in science journals One formulation is that if journals in a field are sorted by number of articles into three groups each with about one third of all articles then the number of journals in each group will be proportional to 1 n n 1 There are a number of related formulations of the principle In many disciplines this pattern is called a Pareto distribution As a practical example suppose that a researcher has five core scientific journals for his or her subject 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 i e 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 etc journals most researchers quickly realize that there is little point in looking further Different researchers have different numbers of core journals and different Bradford multipliers But the pattern holds quite well across many subjects and may well be a general pattern for human interactions in social systems Like Zipf s law to which it is related we do not have a good explanation for why it works but knowing that it does is very useful for librarians What it means is that for each specialty it is sufficient to identify the core publications for that field and only stock those very rarely will researchers need to go outside that set However its impact has been far greater than that Armed with this idea and inspired by Vannevar Bush s famous article As We May Think Eugene Garfield at the Institute for Scientific Information in the 1960s developed a comprehensive index of how scientific thinking propagates His Science Citation Index SCI had the effect of making it easy to identify exactly which scientists did science that had an impact and which journals that science appeared in It also caused the discovery which some did not expect that a few journals such as Nature and Science were core for all of hard science The same pattern does not happen with the humanities or the social sciences The result of this is pressure on scientists to publish in the best journals and pressure on universities to ensure access to that core set of journals On the other hand the set of core journals may vary more or less strongly with the individual researchers and even more strongly along schools of thought divides There is also a danger of over representing majority views if journals are selected in this fashion Bradford s law is also known as Bradford s law of scattering or the Bradford distribution as it describes how the articles on a particular subject are scattered throughout the mass of periodicals 2 Another more general term that has come into use since 2006 is information scattering an often observed phenomenon related to information collections where there are a few sources that have many items of relevant information about a topic while most sources have only a few 3 This law of distribution in bibliometrics can be applied to the World Wide Web as well 4 Contents 1 Scattering 2 Law s interpretations 3 Related laws and distributions 4 See also 5 Notes 6 References 7 External linksScattering EditHjorland and Nicolaisen 2005 p 103 identified three kinds of scattering Lexical scattering The scattering of words in texts and in collections of texts Semantic scattering The scattering of concepts in texts and in collections of texts Subject scattering The scattering of items useful to a given task or problem They found that the literature of Bradford s law including Bradford s own papers is unclear in relation to which kind of scattering is actually being measured Law s interpretations EditThe interpretation of Bradford s law in terms of a geometric progression was suggested by V Yatsko 5 who introduced an additional constant and demonstrated that Bradford distribution can be applied to a variety of objects not only to distribution of articles or citations across journals V Yatsko s interpretation Y interpretation can be effectively used to compute threshold values in case it is necessary to distinguish subsets within a set of objects successful unsuccessful applicants developed underdeveloped regions etc Related laws and distributions EditBenford s law originally used to explain apparently non uniform sampling Lotka s law describes the frequency of publication by authors in any given field Power law a general mathematical form for heavy tailed distributions with a polynomial density function In this form these laws may all be expressed and estimates derived Zeta distribution Zipf s law originally used for word frequencies Zipf Mandelbrot lawSee also EditPageRank The Long TailNotes Edit Black Paul E 2004 12 12 Bradford s law in Dictionary of Algorithms and Data Structures U S National Institute of Standards and Technology Retrieved 2007 10 24 VICKERY B C 1948 01 01 Bradford s Law of Scattering Journal of Documentation 4 3 198 203 doi 10 1108 eb026133 ISSN 0022 0418 Information Scattering Encyclopedia of Library and Information Sciences Third Edition CRC Press 2009 12 17 pp 2564 2569 doi 10 1081 E ELIS3 120043255 ISBN 978 0 203 75763 5 Turnbull Don 1997 Bibliometrics and the World Wide Web University of Toronto Technical Report Archived from the original on 2007 04 02 Retrieved 2007 07 05 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Yatsko V A 2012 The interpretation of Bradford s law in terms of geometric progression Automatic Documentation and Mathematical Linguistics 46 2 112 117 doi 10 3103 S0005105512020094 S2CID 255432905 References Edit Scholia has a topic profile for Bradford s law Bradford Samuel C Sources of Information on Specific Subjects Engineering An Illustrated Weekly Journal London 137 1934 26 January pp 85 86 Reprinted as Bradford Samuel C Sources of information on specific subjects Journal of Information Science 10 4 1985 October pp 173 180 1 Hjorland Birger and Nicolaisen Jeppe 2005 Bradford s law of scattering ambiguities in the concept of subject in Proceedings of the 5th International Conference on Conceptions of Library and Information Science 96 106 Nicolaisen Jeppe and Hjorland Birger 2007 Practical potentials of Bradford s law A critical examination of the received view Journal of Documentation 63 3 359 377 Available here and here Suresh K Bhavnani Concepcio n S Wilson Information Scattering Available 2 External links EditIn Oldenburg s Long Shadow Librarians Research Scientists Publishers and the Control of Scientific Publishing Retrieved from https en wikipedia org w index php title Bradford 27s law amp oldid 1168193546, wikipedia, wiki, book, books, library,
