The RefTverskyCombo score assigns an alpha value of 0.95 to the CSM query molecule as the main self-overlap term, meaning, in the context of this study, that it emphasizes the matching of the CSM (which by design of the data sets is the superstructure). The FitTverskyCombo score, on the contrary, assigns a beta value of 0.95 to the fit (knowledge base) molecule, emphasizing the match of the non-CSM (substructure). Note that the RefTverskyCombo and FitTverskyCombo scores can have values greater than 2, because the overlap of two compounds can be larger than a molecule's self-overlap.