Assessing the reliability and validity of Google Scholar indicators : The case of social sciences in Italy

Google Scholar is an appealing data source for the measurement of scientific production in the social sciences and humanities (SSH) fields. Its appeal derives from its extensive coverage of the literature. This contrasts with issues of data quality, which are still quite controversial. This chapter aims to evaluate the reliability and validity of bibliometric indicators taken from Scholar as well as their coverage of the scientific production in the social sciences. The analysis will be based on a comparison of Scholar with other bibliometric data sources (Web of Science and Scopus) plus an institutional dataset. The reliability of Scholar indicators will be investigated through correlational analysis, while their validity will be assessed using different external criteria (the results of national evaluation procedures based on a peer review approach). The analysis will be developed for the population of Italian university professors in a subset of SSH: political philosophy, history, political science and sociology. The final discussion of the results will take into account the various purposes that bibliometric exercises try to achieve.