A multi-centrality index for graph-based keyword extraction.

•Analyses of nine centrality measures with Structural Holes used for the first time in keyword extraction.•Centrality measures are correlated and with statistical similar performance when finding keywords.•Proposal of the multi-centrality index (MCI) to combine the most representative measures.•MCI achieves a high precision, recall, and F1-score with statistical significance.•Clustering algorithms could not identify well the keyword group as the MCI approach.