Highly cited researchers: a moving target

Highly cited researchers are a category of researchers defined by scientometric rules relating to counts of citations to their scholarly articles. The designation often refers to researchers identified according to scientometric rules specified by the Institute of Scientific Information (ISI) and its commercial affiliates; we denote these categories as HCR. The 2001 ISI rules (HRC.1) used membership thresholds derived from the total citation counts to an author's corpus in a specified research field and time window. The modified 2013 rules also include counts of individual highly cited publications (HCR.2), while the foreshadowed 2018 rules introduce the concept of cross-field influence (HCR.3). The HCR category is a popular, albeit flawed, indicator of outstanding individual researchers. HCR membership has been used as the basis for many studies of research excellence, including the use of an institution's HCR count as an indicator in the Academic Ranking of World Universities (ARWU). The paper traces the development of the HCR category and its use by ARWU, providing insights into the social construction of research indicators and their potential to change research practice.