The Influence of Changing Marginals on Measures of Inequality in Scholarly Citations: Evidence of Bias and a Resampling Correction
The Influence of Changing Marginals on Measures of Inequality in Scholarly Citations: Evidence of Bias and a Resampling Correction
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DOI：
10.15195/v7.a13
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发表时间：
2020-08-10
影响因子：
3.4
通讯作者：
Stovel, Katherine
中科院分区：
文献类型：
--
作者：
Kim, Lanu;Adolph, Christopher;Stovel, Katherine
学者们一直在争论数字环境的变化是否导致了科学引文的更集中或更分散，但这场辩论很少关注出版环境的其他变化如何影响常用的不平等衡量标准。通过蒙特卡罗实验，我们证明了各种不平等度量——包括基尼系数、赫芬达尔-赫希曼指数和被引用文章的百分比——随着文章总数和引用次数的增加而显著地向下倾斜。我们提出并验证了基于重采样的“边际偏差”校正方法，并将此校正应用于1996年至2014年四个广泛科学领域（健康、人文、数学和计算机科学以及社会科学）的Web of Science数据中学术引文分布的经验数据。我们发现，在每个领域，近年来引文不平等的明显下降大部分是边际偏差的产物，正如最明显的引文不平等的领域间差异一样。研究人员使用不平等度量来比较引用分布和其他分布在零边界或接近零边界的许多情况下，应该仔细解释这些指标，并考虑变化的边缘的影响。
Scholars have debated whether changes in digital environments have led to greater concentration or dispersal of scientific citations, but this debate has paid little attention to how other changes in the publication environment may impact the commonly used measures of inequality. Using Monte Carlo experiments, we demonstrate that a variety of inequality measures-including the Gini coefficient, the Herfindahl-Hirschman index, and the percentage of articles ever cited-are substantially biased downward by increases in the total number of articles and citations. We propose and validate a resampling-based correction for this "marginals bias" and apply this correction to empirical data on scholarly citation distributions using Web of Science data covering four broad scientific fields (health, humanities, mathematics and the computer sciences, and the social sciences) from 1996 to 2014. We find that in each field the bulk of the apparent decline in citation inequality in recent years is an artifact of marginals bias, as are most apparent interfield differences in citation inequality. Researchers using inequality measures to compare citation distributions and other distributions with many cases at or near the zero-bound should interpret these metrics carefully and account for the influence of changing marginals.