where ∆E low IJK indicates the three-body correction evaluated using a low-level method (force field), and the cutoff τ 3 was set to 0.25 kJ/mol following some testing. This approach proves to be far more efficient than distancebased screening, if the cutoffs are set (in either case) so as to achieve ∼ 1 kcal/mol fidelity with respect to a supersystem calculation at the same level of theory. Fourbody terms were omitted in our previous work, with the effect that 1 kcal/mol fidelity requires an additional supersystem correction at a low level of theory, in order to capture four-body polarization that is neglected by MBE(3).