Features based on connectivity, shape and PageRank were extracted, giving a total of 19 Graph features.
the features used were: percentage of nodes with degrees one, two and three; the highest, second-highest and median degree in the graph; the highest degree divided by the total number of links; the top three PageRank values in the graph, their respective negative logarithms, and their essay length-normalized versions; the median PageRank value in the graph, its negative log and essay length-normalized version.