Dependence of Lotka’s law parameters on the scientific area

The main aim of this paper was to examine whether the characteristics of the Lotka distribution of publications (in particular, the changes that the two parameters, n and c, undergo) constitute an indicator of the structure of influence in a scientific field. A quasi-experimental method was used to estimate the parameters of Lotka's law in a number of scientific areas (by means of a series of searches in the Scopus database). The study was performed on 90 sets of author productivity data (resulting from a combination of 10 areas, 14 countries, and 3 time periods). Both the exponent of the law, n (i.e., the slope of the log-log plot), and the constant c (the fraction of authors with only a single publication) were found to depend on the state of development of the scientific area, on its productivity, on the country, and on the time period being studied. A characteristic that distinguished the so-called "hard sciences" from the "social sciences and humanities" was the level of co-authorship, with the average number of authors per publication being greater in science than in the social sciences and humanities. The empirical results show a picture of the behaviour of the Lotka distribution in different situations, due to different causes. This could be interesting as a better understanding of these regularities may allow them to be incorporated into the theoretical context.