The best performing model in Table , according to both MBE(2) and MBE(3) calculations, is the d = 6 Å model. This construction also affords the largest model for each of the four protein-ligand complexes that we consider, and includes residues that were not picked up in the rinrus constructions or even by the τ 2B criterion. At the same time, a strictly distance-based construction almost certainly includes unimportant residues, leading to systematically larger models. For the T4-lysozymes 181L and 1LI2, the 6 Å model affords a smaller error at the MBE(2) level as compared to the τ 2B -derived model, but for those systems the binding site is more spherical (and the ligand is much smaller) as compared to 1O48 and 1BOZ. Convergence to the supermolecular value of ∆E int is slower for the latter two systems. Models generated using the rinrus toolkit in either its "Probe" or "Arpeggio" configurations (Section 2 .3) are generally similar to one another although Arpeggio includes a slightly larger number of residues. (In each case considered here, residues selected by the Probe model represent a proper subset of those selected using the Arpeggio construction.) While the Arpeggio models are slightly larger, they are not significantly or consistently more accurate.