Crediting multi-authored papers to single authors

A fair assignment of credit for multi-authored publications is a long-standing issue in scientometrics. In the calculation of the h-index, for instance, all co-authors receive equal credit for a given publication, independent of a given author’s contribution to the work or of the total number of co-authors. Several attempts have been made to distribute the credit in a more appropriate manner. In a recent paper, Hirsch has suggested a new way of credit assignment that is fundamentally different from the previous ones: All credit for a multi-author paper goes to a single author, the called “α-author”, defined as the person with the highest current h-index (not the highest h-index at the time of the paper’s publication) (Hirsch, 2019). The collection of papers this author has received credit for as α-author is then used to calculate a new index, hα, following the same recipe as for the usual h index. The objective of this new assignment is not a fairer distribution of credit, but rather the determination of an altogether different property, the degree of a person’s scientific leadership. We show that given the complex time dependence of h for individual scientists, the approach of using the current h value instead of the historic one is problematic, and we argue that it would be feasible to determine the α-author at the time of the paper’s publication instead. On the other hand, there are other practical considerations that make the calculation of the proposed hα very difficult. As an alternative, we explore other ways of crediting papers to a single author in order to test early career achievement or scientific leadership.