Methodology

Overview

  • The Highly Cited Researchers list from Clarivate Analytics identifies scientists and social scientists who have demonstrated significant influence through publication of multiple highly cited papers during the last decade.
  • Researchers are selected for their exceptional performance in one or more of 21 fields (those used in Clarivate Analytics Essential Science Indicators, or ESI) or across several fields.
  • Approximately 6,000 researchers are named Highly Cited Researchers in 2018 – some 4,000 in specific fields and about 2,000 for cross-field performance. This is the first year that researchers with cross-field impact are identified.
  • The number of researchers selected in each field is based on the square root of the population of authors listed on the field’s highly cited papers. The number of those with cross-field influence is determined by finding those who have influence equivalent to those identified in the 21 fields.
  • For the 2018 Highly Cited Researchers analysis, the papers surveyed were published and cited during 2006-2016 and which then ranked in the top 1% by citations for their ESI field and year (the definition of a highly cited paper).
  • The threshold number of highly cited papers for selection differs by field, with Clinical Medicine requiring the most and Agricultural Sciences, Economics & Business, and Pharmacology & Toxicology the least.
  • A second criterion for selection is a citation count to highly cited papers that ranks a researcher in the top 1% by citations in an ESI field for the period surveyed.
  • To identify researchers with cross-field impact, highly cited paper and citation counts are normalized through fractionating according to the thresholds required for each field (thus, each Clinical Medicine paper, has a smaller unit fraction than one in Agricultural Sciences). Citations counts are fractionated in a similar manner. If the sum of the publication counts and the sum of the citation counts for a researcher equals 1.0 or more, the individual exhibits influence equivalent to a researcher selected in one or more ESI defined fields and is therefore selected as a Highly Cited Researcher for exceptional cross-field performance.
  • There is no unique or universally agreed concept of what constitutes exceptional research performance and elite status in the sciences and social sciences. Consequently, no quantitative indicators will point to a list that satisfies all expectations or requirements. Moreover, a different basis or formula for selection could generate a different – though likely overlapping – list of names. Thus, the absence of a name on our list cannot be interpreted as inferior performance or stature in comparison to those selected. To understand both the meaning and the inevitable limitations of our analytical approach, a careful reading of the methodology is required.

 

Click here for a detailed description of the purpose and methodology of Highly Cited Researchers.

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