  As digital collections of scientific literature are widespread and used
frequently in knowledge-intense working environments, it has become a challenge
to identify author names correctly. The treatment of homonyms is crucial for
the reliable resolution of author names. Apart from varying handling of first,
middle and last names, vendors as well as the digital library community created
tools to address the problem of author name disambiguation. This technical
report focuses on two widespread collections of scientific literature, Web of
Science (WoS) and Scopus, and the coverage with author identification
information such as Researcher ID, ORCID and Scopus Author Identifier in the
period 1996 - 2014. The goal of this study is to describe the significant
differences of the two collections with respect to overall distribution of
author identifiers and its use across different subject domains. We found that
the STM disciplines show the best coverage of author identifiers in our dataset
of 6,032,000 publications which are both covered by WoS and Scopus. In our
dataset we found 184,823 distinct ResearcherIDs and 70,043 distinct ORCIDs. In
the appendix of this report we list a complete overview of all WoS subject
areas and the amount of author identifiers in these subject areas.
