Google Scholar's ranking algorithm: The impact of citation counts (An empirical study)

Google Scholar is one of the major academic search engines but its ranking algorithm for academic articles is unknown. In a recent study we partly reverse-engineered the algorithm. This paper presents the results of our second study. While the previous study provided a broad overview, the current study focused on analyzing the correlation of an article's citation count and its ranking in Google Scholar. For this study, citation counts and rankings of 1,364,757 articles were analyzed. Some results of our first study were confirmed: Citation counts is the highest weighed factor in Google Scholar's ranking algorithm. Highly cited articles are found significantly more often in higher positions than articles that are cited less often. Therefore, Google Scholar seems to be more suitable for searching standard literature than for gems or articles by authors advancing a view different from the mainstream. However, interesting exceptions for some search queries occurred. In some cases no correlation existed; in others bizarre patterns were recognizable, suggesting that citation counts sometimes have no impact at all on articles' rankings.