  Bibliometric analysis is increasingly used to evaluate and compare research
performance across geographical regions. However, the problem of missing
information from author addresses has not attracted sufficient attention from
scholars and practitioners. This study probes the missing data problem in the
three core journal citation databases of Web of Science (WoS). Our findings
reveal that from 1900 to 2015 over one-fifth of the publications indexed in WoS
have completely missing information from the address field. The magnitude of
the problem varies greatly among time periods, citation databases, document
types, and publishing languages. The problem is especially serious for research
in the sciences and social sciences published before the early 1970s and
remains significant for recent publications in the arts and humanities. Further
examinations suggest that many records with completely missing address
information do not represent scholarly research. Full-text scanning of a random
sample reveals that about 40% of the articles have some address information
that is not indexed in WoS. This study also finds that the problem of partially
missing address information for U.S. research has diminished dramatically since
1998. The paper ends by providing some discussion and tentative remedies.
