Visualization of the cumulative sum of biologically positive classes among the top-80 classes for each scoring function. Figure shows how many biologically positive classes each method discovers across their top ranks from ALL dataset. Different scoring functions are marked similarly to earlier figures. Notice that although GSZ, iGA and t-test first show equal performance, GSZ outweigh other methods across the later ranks. A more detailed view is provided in the supplementary table S2 [see additional file 8].