To elucidate the rationale behind the performance of RMR6 in selecting a good pose we plotted the RMR6 of the pose with the smallest RMSD against the score of the crystal pose in Figure . For 'Top Percent' values greater than 10%, there is a clear separation between the poses within 2.0 Å and the poses far from the crystal pose (failures). These failures cluster above the identity line, indicating RMR under-scores these complexes during sampling. Since these cases are rare, it is best to evaluate them on a per ligand basis, which we do in the following section.