Google scholar as a measure of impact
Antonio G. Valdecasas and Uta Grothkopf write:
Leaving aside the adequacy of using citation counts to evaluate scientists' merit (as discussed for instance by Peter Lawrence in Nature 422, 259-261; 2003), there is the associated problem of exhaustive gathering of citations for certain kinds of publications, in particular monographs and book series that are not routinely covered by the Science Citation Index (SCI).
In countries like Spain where, as Lawrence points out, bureaucrats carry out scientists' assessment with "formulaic precision", there is, therefore, a risk of underrating this type of publication. Examples can be as extreme as to receive a dictum of almost 'no impact' for a monograph whose articles have been cited more than 150 times in journals included in the SCI, 19 times in non-SCI journals, 10 times in proceedings and which contains several articles in 'rare' languages such as Russian and Chinese. These citation results can be easily found through a simple search in Google Scholar. Not a bad citation number for a discipline (morphometrics) that has a mean number of citations for the period 1996-2005 of 8.5 (n= 1,408) citations per article, but most of them would be lost if one relies exclusively on the SCI.
Maybe the days of the SCI are numbered, as is already the case in disciplines such as astronomy, where alternative services are used. If impact is to be used as a metric that affects people directly, then databases like Google Scholar -- free, accessible to everybody, and non-discriminatory against languages other than English -- could provide a tool of universal coverage for bureaucrats and evaluation committees to discover the real impact of publications and hence to be less biased in the distribution of benefits.
Antonio G. Valdecasas
Museo Nacional de Ciencias Naturales, Madrid, Spain
Uta Grothkopf
European Southern Observatory, Garching, Germany.
Comments
For a fuller picture of the impact, clearly searches of MathSciNet are required in Mathematics (see Yamamoto, http://sulair.stanford.edu/scholarly_com/colloquium/presentations/yamamoto.pdf), Chem Abstracts in Chemistry, ADS in astro, and at minimum a *combination* of Scopus, WoS, and GS in all other subjects. See Bakkalbasi et al's article on this: http://eprints.rclis.org/archive/00006080/.
Nevertheless, SCI is still necessary and useful.
Posted by: Christina Pikas | July 3, 2007 03:53 PM
Scopus is also better, although not perfect, than ISI at counting citations.
Certainly, it is better than Google Scholar, which was not designed to provide such kind of service.
Posted by: Miguel Araújo | July 17, 2007 11:47 AM
Paraphrasing Bertolt Brecht, a data base is worth what a skilled human can get from it. The number of citations at present (3/20/2008) of either the entire ‘Contributions to Morphometrics’ or particular chapters sum up to 336. It took an IT specialist at IEDCYT, CSIC, Madrid, several days to get the full count. In any case, all those citations can be found in Google Scholar, but it takes time. But it takes time too to query SCIExpanded and Scopus for specific citations. However, the points we were making, and the ones we would like to stress are that Google Scholar is free and does not discriminate against languages other than English, whereas SCIExpanded and Scopus discriminate and are not free.
Posted by: Antonio G. Valdecasas | April 1, 2008 02:36 PM