Google Scholar uses the same underlying technologies as regular Google, but limits the pages and links it crawls or analyzes to "scholarly" domains, such as academic institutions, government research portals, professional and scholarly societies, and commercial publishers of scholarly books and journals. The ranking algorithm is also slightly different, since it also takes into account the number of citations from other scholarly sources.For more information on how Google and other web search engines work, see here.
Advantages of Using Google Scholar:
- The search experience is familiar to just about everybody, making Google Scholar easy to use.
- The nature of the scholarly sources Google Scholar indexes makes SEO techniques more difficult to carry out. This means that the page ranking more accurately reflects the page's actual relevance.
- Citation count is a well-known and widely used measure of research "quality." By incorporating this into its ranking engine, Google Scholar favors the most influential resources in a field, which can be important to read when conducting your own research.
- By searching only scholarly websites, most questionable or fraudulent material is eliminated.
- The smaller pool of web pages means that the number of results returned will be less and that precision and recall may be greater.
Disadvantages of Using Google Scholar:
- Because Google Scholar uses the same technologies as regular Google, it cannot index any content behind paywalls or login screens. This means that in the case of most books and journals, it cannot do a full-text search, but is limited to searching whatever data the publisher makes publicly accessible.
- Google's underlying technology also means that the results you get will be affected by your previous searches. Google tracks your search history to try to tailor its results to match what it thinks are your interests and needs.
- There is no controlled vocabulary, so precision and recall are still low. You can expect any search in Google Scholar to return many irrelevant results and to miss many relevant results.
- The lack of a controlled vocabulary also means that searches can only be refined by combining many different terms with Boolean operators, which is both confusing and time consuming.
- By indexing only scholarly resources, Google Scholar misses certain types of resources altogether, such as company white papers, product specifications, or company data (such as financial reports) that may be important for your research.