To validate our models, we used a subset of the PDBbind refined set referred to as the "core set". This is obtained by clustering the proteins in the refined set at 90% sequence identity and selecting three or five (depending on the version of PDBbind) representatives of each cluster for which the corresponding ligands have a broad range of binding affinity values, resulting in a diverse, non-redundant set of protein-ligand complexes. We repeated our tests using the core sets from the 2007, 2013, and 2016 releases of PDBbind. These versions of the core set were used as the "scoring power" benchmark in the Comparative Assessment of Scoring Functions (CASF) exercises: CASF2009 32 , CASF2013 17,18 , and CASF2016 33 respectively, allowing our results to be compared directly to previously published scoring function benchmarks. We used the test sets corresponding to all three CASF benchmarks since the contents of each test set are substantially different to the others and so each set offers a different challenge for a scoring function. Excluding proteins and ligands that could not be parsed by OpenBabel or RDKit resulted in 2007, 2013, and 2016 core sets containing 196, 180, and 276 structures respectively. The full list of structures omitted from the core sets because of parsing failures is included in the Supporting Information. These test sets are relatively small, making it difficult to identify statistically-significant differences in results generated by different models. To partially overcome this shortcoming without deviating from widely-used benchmarks, we combined the structures from each core set into a fourth test set with duplicate strictures removed. This combined test set numbered 525 structures, almost twice the size of the PDBbind 2016 core set.