Lotka's law

Lotkas law is a 1926 fixed excepted by Alfred J. Lotka scaling law, which finds use in scientometrics. It shows the relationship between the number of publications a person and the number of people with the same high discharge publication. It was set up for the number of scientific journal articles and states that the number of people who write articles n is proportional to n -2 ( later results suggest rather an exponent of -1.7 instead of -2 close to what not alter the basic statement of the law changes ). William B. Shockley pointed out in a 1957 essay published for the first time out that in consideration of multiple authorship of scientific papers and weighting the proportion of each different authors exponents are generated. Weighting of authorship means that, for example, in a work of four authors each author 0.25 publications are attributed.

A similar, but much simpler distribution defines the Pareto distribution ( the 80-20 rule ), shall be covered by the 80 % of information needs of 20 % of all sources.

The general formula is:

Example

For 100 authors, each with an average write in a given period an article come:

Since its discovery, among other bibliometrically, epistemologically and sociologically interesting law has been repeatedly confirmed and found also in other areas, such as in the number of employees and the extent of their contributions to open source projects.

The number of citations per publication assume in the ratio of n- 2, n- 3 from 5 to.

At the ends of the Lotka distribution is slightly bent, because the volume of publications, a person down ( 1 item) and above ( depending on the case ) there are limits.