What is Google Scholar?
Google Scholar, launched in 2004, is a search engine for scholarly literatures such as peer-reviewed articles, preprints, books, theses, conference papers, monographs etc. Besides, its legal database indexes the US court cases.
Google scholar database contains both full text and metadata of papers. According to research conducted in 2014 it contains roughly 160 million documents. Nearly 90% of all scientific articles published in English can be found through Google Scholar. It covers every discipline; though some disciplines such as humanities are underrepresented (indexed). Google Scholar links to major publishers and repositories. Nevertheless, some webpages are not indexed - for instance faculty webpages. Microsoft Academic, Worldwide Science, ScienceDirect and ResearchGate are some of Google Scholar’s competitors.
Google Scholar, like Scopus and Web of Science, has citation counting capabilities and also supports major bibliography managers. Furthermore, it allows scholars to create a personal profile page.
There are criticisms directed at Google Scholar. Firstly, its ranking system focuses more on quantity- i.e. on a citation count and the number of papers an author published. Its citation count is also susceptible to manipulation. Spammers can increase the number of citation a paper can get. Secondly, there are journals that Google Scholar search engine cannot access. Thirdly, there are instances when it indexes predatory journals. This emanates from its approach to index as many journals as possible. This undermines its quality. Finally, filtering options in Google Scholar is limited. Therefore, it is not easy to search within a discipline or a journal article