RESEARCH ARTICLE Recency predicts bursts in the evolution of author citations Filipi Nascimento Silva 1 , Aditya Tandon 2 , Diego Raphael Amancio 3 , Alessandro Flammini 1,2 , Filippo Menczer 1,2 , Staša Milojevic  2 , and Santo Fortunato 1,2 1 Indiana University Network Science Institute, Indiana University, Bloomington, USA 2 Center for Complex Networks and Systems Research, Luddy School of Informatics, Computing and Engineering, Indiana University, Bloomington, USA 3 Institute of Mathematics and Computer Science, University of São Paulo, São Carlos, Brazil Keywords: author citations, bursts, model, preferential attachment, recency ABSTRACT The citations process for scientific papers has been studied extensively. But while the citations accrued by authors are the sum of the citations of their papers, translating the dynamics of citation accumulation from the paper to the author level is not trivial. Here we conduct a systematic study of the evolution of author citations, and in particular their bursty dynamics. We find empirical evidence of a correlation between the number of citations most recently accrued by an author and the number of citations they receive in the future. Using a simple model where the probability for an author to receive new citations depends only on the number of citations collected in the previous 12–24 months, we are able to reproduce both the citation and burst size distributions of authors across multiple decades. 1. INTRODUCTION Citations are one of the most widely used indicators of academic impact and, as such, they have been studied extensively (Waltman, 2016). Despite a lack of consensus about the relevance of citations as an indicator of quality (Leydesdorff, Bornmann, et al., 2016; Martin & Irvine, 1983), papers and authors with a large number of citations are considered influential. Understanding the process of citation accumulation is one of the central questions in science of science (Fortunato, Bergstrom, et al., 2018). The major challenge lies in delineating how the interplay between factors related to the quality and relevance of papers and factors related to author popularity contribute to the process of citation accumulation. The first model of citation dynamics for papers was proposed by de Solla Price (1976). It is based on the principle of cumulative advantage: the probability of a paper to be cited is proportional to the number of citations the paper already has, up to an additive constant. This principle leads to a broad distribution of citations: most papers have just a few citations, while a minority of top-cited papers accounts for a considerable fraction of all citations (de Solla Price, 1965; Radicchi, Fortunato, & Castellano, 2008; Thelwall, 2016). In network science (Barabàsi, 2016; Newman, 2010) the principle of cumulative advantage is called preferential attachment and it has been invoked to explain the broad degree distributions observed in many real networks (Barabàsi & Albert, 1999). The phenomenon is also known as the rich-get-richer or Matthew effect in the sociology of science, where certain psychosocial pro- cesses lead the community to give disproportionately large credit to individuals who already an open access journal Citation: Silva, F. N., Tandon, A., Amancio, D. R., Flammini, A., Menczer, F., Milojević, S., & Fortunato, S. (2020). Recency predicts bursts in the evolution of author citations. Quantitative Science Studies, 1(3), 1298–1308. https://doi.org/10.1162/ qss_a_00070 DOI: https://doi.org/10.1162/qss_a_00070 Supporting Information: https://www.mitpressjournals.org/doi/ suppl/10.1162/qss_a_00070 Received: 1 December 2019 Accepted: 2 May 2020 Corresponding Author: Santo Fortunato santo@indiana.edu Handling Editor: Ludo Waltman Copyright: © 2020 Filipi Nascimento Silva, Aditya Tandon, Diego Raphael Amancio, Alessandro Flammini, Filippo Menczer, Staša Milojević, and Santo Fortunato. Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license. The MIT Press Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/qss_a_00070 by guest on 26 September 2021