Empirical Evidences in Citation-Based Search Engines: Is Microsoft Academic Search dead?

摘要

The goal of this working paper is to summarize the main empirical evidencesprovided by the scientific community as regards the comparison between the twomain citation based academic search engines: Google Scholar and MicrosoftAcademic Search, paying special attention to the following issues: coverage,correlations between journal rankings, and usage of these academic searchengines. Additionally, selfelaborated data is offered, which are intended toprovide current evidence about the popularity of these tools on the Web, bymeasuring the number of rich files PDF, PPT and DOC in which these tools arementioned, the amount of external links that both products receive, and thesearch queries frequency from Google Trends. The poor results obtained by MASled us to an unexpected and unnoticed discovery: Microsoft Academic Search isoutdated since 2013. Therefore, the second part of the working paper aims atadvancing some data demonstrating this lack of update. For this purpose wegathered the number of total records indexed by Microsoft Academic Search since2000. The data shows an abrupt drop in the number of documents indexed from2,346,228 in 2010 to 8,147 in 2013 and 802 in 2014. This decrease is offeredaccording to 15 thematic areas as well. In view of these problems it seemslogical not only that Microsoft Academic Searchwas poorly used to search forarticles by academics and students, who mostly use Google or Google Scholar,but virtually ignored by bibliometricians