Web of Science with the Conference Proceedings Citation Indexes: the case of computer science Judit Bar-Ilan Received: 4 December 2009 / Published online: 12 January 2010 Ó Akade ´miai Kiado ´, Budapest, Hungary 2010 Abstract In September 2008 Thomson Reuters added to the ISI Web of Science (WOS) the Conference Proceedings Citation Indexes for Science and for the Social Sciences and Humanities. This paper examines how this change affects the publication and citation counts of highly cited computer scientists. Computer science is a field where proceedings are a major publication venue. The results show that most of the highly cited publications of the sampled researchers are journal publications, but these highly cited items receive more than 40% of their citations from proceedings papers. The paper also discusses issues related to double-counting, i.e., when a given work is published both in a proceedings and later on as a journal paper. Keywords Conference proceedings citation indexes Á Computer science Á Publication counts Á Citation counts Á Re-publishing Introduction The citation indexes established by Eugene Garfield are selective databases. In his book, Garfield (1979) explains that there are several reasons for selecting which journals to index: it is impractical or even impossible to list all scientific journals and it is not economically feasible to index all journals. Thus there has to be a selection process, which is based on the core journals in each discipline (Bradford 1934). However, when con- sidering a multidisciplinary database, it turns out that much more than the core is covered, This work was first published as a proceedings paper in the Proceedings of the 12th International Conference on Scientometrics and Informetrics. This is an updated and extended version (a new expression) of that work. Errors in the citation and publication counts of the researchers in the sample were corrected. The list of references is identical in both versions, except for the reference (Wilson 1968), which has been suggested by Howard White. J. Bar-Ilan (&) Department of Information Science, Bar-Ilan University, Rmat Gan 52900, Israel e-mail: barilaj@mail.biu.ac.il 123 Scientometrics (2010) 83:809–824 DOI 10.1007/s11192-009-0145-4