< Figure here > To further quantify scaffold diversity based on the Bemis-Murcko scaffolds, we used cyclic system recovery curves. As documented elsewhere, based on the scaffolds count, the fraction of cyclic systems is plotted against the cumulative fraction of the database. A diagonal represents maximum scaffold diversity, i.e., each compound will have its chemical scaffold. A vertical line represents the minimum scaffold diversity (all compounds have the same scaffold). Figure shows the cyclic system recovery curves for all data sets. The curves can be further characterized by the area under the curve, AUC (maximum diversity: AUC = 0.5; minimum diversity: AUC = 1.0). Table in the Supporting Information summarizes the AUC values for the 11 data sets. The results show that ChemDiv is the least diverse, followed (AUC = 0.87) by OTAVA DNMT3b. In contrast, TocrisScreen and Targetmol are the most diverse (AUC <= 0.56).