Salton's Cosine, Jaccard Index and Pearson's Correlation: comparing normalized and absolute indexed in author co-citation analysis

This research aims to conduct a comparative study between the absolute and normalized indicators for Author Co-citation Analysis, namely: Salton's Cosine (Sc), Jaccard Index (JI) and Pearson's correlation (r). As data source, we used the articles from the journal Scientometrics on Scopus database in the subject Metric Studies. We retrieved 234 articles in the 2013-2014 period, in June 2015. We identified 9,327 cited researchers. We generated the absolute matrix with the most co-cited authors, and proceeded to normalizations, through the three processes. In order to compare the results of the absolute matrix with their respective normalized indexes - Salton's Cosine (Sc), Jaccard Index (JI) and Pearson's correlation (r) - we calculated Spearman's correlation. We present the scatter plots and concluded that Salton's Cosine is preferred, from the research objectives, the nature of the data and greater significance in relation to Spearman's correlation.