Reference publication year spectroscopy: A bibliometric method for the analysis of the historical roots of research fields

In research evaluations, the impact of scientific publications is often measured by the number of their citations with the help of quantitative (bibliometric) methods. Bibliometric data support and complement the work of experts. Alternatively, one can also examine the literature of a chosen research field with respect to most frequently cited publications, authors, and journals. It is particularly interesting for the origin and development of a research field to understand which publications have, in the course of time, made an outstanding contribution to its development. This opens up an opportunity to pursue the development of research fields chronologically and to quantify the weight of individual publications. The data are based on the scientific community as a whole and they provide, e. g. for science historians, the potentially important contributions they should consider in their scientific work in order to avoid incompleteness and distortions. The appropriate bibliometric method is called Reference Publication Year Spectroscopy (RPYS) and it makes use of the fact that very frequently cited papers occur as prominent peaks in the corresponding publication years. A program called Cited References Explorer (CRExplorer) has been developed for the final analysis. In this paper, we would like to present the RPYS method on the basis of two selected examples and discuss its application to topics of the history of science. The result of our analysis reflects the knowledge of the scientific community as a whole: one can find all the essential early contributions cited in the corresponding scientific historical literature regarding a specific research field. The method works without any additional assumptions and thus avoids, e.g. a personal selection, which is inevitable in the case of individual authors of scientific historical publications.