Finally, the PDBbind core set (CASF-2016) is a subset of the refined set widely used as benchmarking data for evaluating docking and scoring methods. The latest compiled version (v.2016) contains 285 protein-ligand complexes carefully collected from the refined set using the following selection criteria: (i) protein structures with the identity of sequence higher than 90% were grouped, generating 65 clusters associated with different protein families; (ii) only the clusters composed of at least five members were considered to construct the core set; (iii) for each of these clusters, only the complexes with the lowest, the medium and the highest affinities were selected to the final composition of the core set. From now on, we will refer to the refined set for training and validating machine-learning models (i.e., excluding the core set) .