Communications - August 2012

GS covers more conferences than other academic databases. Unlike some other studies10 we did not find more extended conference coverage in Scopus compared to WoS. This might have been due to increased coverage in WoS in the studies.

Table 2 lists the citation counts in each database; in line with previous studies, the Scopus and WoS citation counts were only a small fraction of those in GS. Our tool thus relied heavily on the unreliable GS to compute RRUs.

Table 3 contrasts the numbers of
relevant citations to the found num-
bers and are partitioned into four cat-
egories—J2J, C2J, J2C, and C2C—to
distinguish whether citing and cited
publications are journal (J) or confer-
ence (C) papers. The last column on
the right combines Scopus and WoS,
where a citation is considered rel-
evant/found as soon as it is relevant/
found in at least one of the two and
missing if found in neither. Table 4
lists the h-indexes computed by the
tool for the databases; the found h-
indexes were based on found cita-
tions and the corrected h-indexes on
relevant citations. The corrected h-
indexes correspond to the h-indexes
we would obtain if a database would
fix all its missing citations. As the
tool gives us a list of missing relevant
citations, we requested corrections
of citation records through the WoS
correction-request form. Most of our
requested corrections were applied
within weeks. We used the tool to col-
lect the numbers presented here be-
fore that correction. As the h-indexes
are based on coverage, the corrected
h-index in one database may be small-
er than the counted h-index in anoth-
er database.

table 2. total number of citations per author and citations in each database.

Author Koen Bart Wilfried

total 2280 1056 1937

WoS

384 (17%) 278 (26%) 745 (38%)

Scopus 531 (23%) 313 (30%) 975 (50%)

ACM

217 (10%) 62 (6%) 10 (1%)

Google 2156 (95%) 842 (80%) 1370 (71%)

CiteSeerX
138 (6%)
20 (2%)
46 (2%)

ments for convincing scholars and researchers from non-CS disciplines to value CS conference papers, though it is precisely those citations that are most underestimated. For example, Koen (listed in the tables) might try to convince a promotion committee that conferences should be valued like journals in his domain by pointing to his high #J2C/(#J2J+#J2C) ratio of 43% in WoS. However, this ratio is not nearly as convincing as the 60% he achieved with corrected WoS records.

We see three potential causes for many of the missing citations: First is overcitation in other databases or inclusion of nonexisting citations; the next experiment demonstrates these possibilities occur to a limited degree. The remaining causes are the incorrect parsing of correct references and the occurrence of incorrect and incomplete references in papers, or so-called miscitations. Some papers have been miscited in more than 165 different ways, 16 with more miscitations among non-English names8 and in papers with more authors. 9 For example, our own work is often miscited because the “De,” “van,” and “den” are incorrectly treated as middle names or because they are capitalized incorrectly. The RRUs we found in WoS and Scopus are more than an order of magnitude higher than the 0.5% and 4.4% found by Meho and Yang. 11 But that difference is not surprising; of all the scientific disciplines, librarians and information scientists probably produce the most accurate citations. Note, however, that our experiments