A previous study ( https://doi.org/10.1007/s11192-020-03457-x ) found a discrepancy between Elsevier’s CiteScore and Clarivate Analytics’ Journal Impact Factor (JIF) in library and information science (LIS) journals. One possibility to explain this discrepancy may lie in the number and type of documents used to calculate these journal-based metrics. Using the top quartile of Scopus-indexed journals from 2011 to 2018, we assessed the number of documents for each journal and year that were indexed in Scopus and in Web of Science (WoS) in six fields of study: LIS, discrete mathematics and combinatorics (DMC), medicine: epidemiology (ME), agriculture and biological sciences (ABS), social science: demography (SSD), and environmental engineering (EE). The number of documents in WoS was higher than those indexed in Scopus for four fields of study: LIS, ME, SSD and EE, with a difference of 1653, 3931, 635 and 197 documents, respectively. For DMC and ABS, Scopus listed more documents than WoS for the same years and journals, the differential being 7 and 1284, respectively. The greater indexing of documents in WoS than in Scopus in four fields of study may explain why the JIF of top-ranking LIS journals is different than their CiteScore. To verify this possibility, one category (DMC) was examined in detail. Of the 16 DMC journals examined, 91.1% were articles, while 8.9% of missing documents were corrections, an erratum, an editorial, an abstract report and in press articles. There were no significant differences between the citation patterns of the missing DMC journals’ documents in Scopus and WoS. Citations to missing documents may impact the CiteScore and JIF and should thus be properly indexed.

中文翻译：

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两个数据库（Scopus 和 Web of Science）中六个学科领域的文献索引差异，以及对基于期刊的指标的影响

之前的一项研究 (https://doi.org/10.1007/s11192-020-03457-x) 发现 Elsevier 的 CiteScore 和 Clarivate Analytics 的期刊影响因子 (JIF) 在图书馆和信息科学 (LIS) 期刊中存在差异。解释这种差异的一种可能性可能在于用于计算这些基于期刊的指标的文档数量和类型。使用 2011 年至 2018 年 Scopus 索引期刊的前四分之一，我们评估了每个期刊和年份在六个研究领域中被 Scopus 和 Web of Science (WoS) 索引的文献数量：LIS、离散数学和组合学(DMC)、医学：流行病学 (ME)、农业和生物科学 (ABS)、社会科学：人口学 (SSD) 和环境工程 (EE)。WoS 中的文档数量高于在 Scopus 中索引的四个研究领域的文档数量：LIS、ME、SSD 和 EE，分别相差 1653、3931、635 和 197 个文档。对于 DMC 和 ABS，Scopus 列出了相同年份和期刊的比 WoS 更多的文件，差异分别为 7 和 1284。在四个研究领域，WoS 中的文献索引比 Scopus 中更多，这可以解释为什么顶级 LIS 期刊的 JIF 与其 CiteScore 不同。为了验证这种可能性，详细检查了一个类别 (DMC)。在审查的 16 种 DMC 期刊中，91.1% 是文章，而 8.9% 的缺失文件是更正、勘误、社论、摘要报告和新闻文章。Scopus 和 WoS 中缺失的 DMC 期刊文献的引用模式没有显着差异。对缺失文档的引用可能会影响 CiteScore 和 JIF，因此应正确编入索引。