PNP_Status is a compound categorization, whereas Frag_coverage_Murcko and NP-likeness have quantitative values for all compounds. Some illustrative examples of marketed drugs that are classified PNP, NonPNP and NPL, and the fragments they contain, are shown in Figure . In addition, the specific NP fragments, fragment combination pairs, and PNP fragment combinations that are found in Clinical and Reference compounds were identified in the post-2008 set, in full and by major target classes. Their relative Clinical versus Reference abundances were estimated using odds ratios. Compound physicochemical properties were added to the dataset, taken from ChEMBL and RDkit. Calculations were performed using Microsoft Excel () and DataWarrior (www.openmolecules.org). Statistical significance (p values) was obtained from t-tests assuming unequal variance for unpaired data, or from Wilcoxon signed rank tests for paired data.