Scopus and Web of Science Core Collection (WoSCC) are the two most authoritative and widely-used bibliographic databases. However, for the double-indexed open access mega journal IEEE Access, we found large discrepancies regarding the numbers of published records based on journal publisher, Scopus, and WoSCC. Considering that Segal’s law will confuse many users and affect the reliability of various metrics derived from these two authoritative bibliographic databases, this study conducted a large scale and thorough comparison between the data collected from the journal publisher’s website and these two bibliographic databases. Apart from different policies towards the index of different document types, this study identified four main representative causes for the discrepancies through case study (including the serious record omission and duplicate entry problems). Possible consequences and solutions were also provided.

Scopus和Web of Science核心收藏（WoSCC）是两个最权威且使用最广泛的书目数据库。但是，对于双索引的开放存取大型期刊IEEE Access，我们发现基于期刊出版商，Scopus和WoSCC的已发表记录数存在很大差异。考虑到Segal的定律将使许多用户感到困惑，并影响从这两个权威书目数据库得出的各种度量的可靠性，因此，本研究对从期刊出版者网站和这两个书目数据库收集的数据进行了大规模，彻底的比较。除了针对不同文档类型的索引采取不同的政策外，这项研究通过案例研究（包括严重的记录遗漏和重复录入问题）确定了导致差异的四个主要原因。还提供了可能的后果和解决方案。