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Normalization of Citation Impact in Economics

59 Pages Posted: 25 Aug 2017  

Lutz Bornmann

Swiss Federal Institute of Technology Zurich

Klaus Wohlrabe

CESifo (Center for Economic Studies and Ifo Institute) - Ifo Institute

Date Written: August 01, 2017

Abstract

This study is intended to facilitate fair research evaluations in economics. Field- and time-normalization of citation impact is the standard method in bibliometrics. Since citation rates for journal papers differ substantially across publication years and Journal of Economic Literature (JEL) classification codes, citation rates should be normalized for the comparison of papers across different time periods and economic subfields. Without normalization, both factors that are independent of research quality bias the results of citation analyses. We introduce two normalized indicators in economics, which are the most important indicators in bibliometrics: (1) the mean normalized citation score (MNCS) compares the citation impact of a focal paper with the mean impact of similar papers published in the same economic subfield and publication year. (2) PPtop 50% is the share of papers that belong to the above-average half in a certain subfield and time period. Since the MNCS is based on arithmetic averages despite skewed citation distributions, we recommend using PPtop 50% for fair comparisons of entities in economics (e.g. researchers, institutions, or countries). In this study, we apply the method to 294 journals (including normalized scores for 192,524 papers) by assigning them to four citation impact classes and identifying 33 outstandingly cited economics journals.

Keywords: bibliometrics, citations, JEL codes, journal ranking, mean normalized citation score (MNCS), citation percentile, PPtop 50%

JEL Classification: A110, A120, A140

Suggested Citation

Bornmann, Lutz and Wohlrabe, Klaus, Normalization of Citation Impact in Economics (August 01, 2017). CESifo Working Paper Series No. 6592. Available at SSRN: https://ssrn.com/abstract=3024474

Lutz Bornmann

Swiss Federal Institute of Technology Zurich ( email )

Lausanne CH-1001
Switzerland
+41 44 632 48 25 (Phone)
+41 44 632 12 83 (Fax)

HOME PAGE: http://www.psh.ethz.ch/people/bornmann/

Klaus Wohlrabe (Contact Author)

CESifo (Center for Economic Studies and Ifo Institute) - Ifo Institute ( email )

Poschinger Str. 5
Munich, 01069
Germany

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