> I understand this argument if you're trying to model the efficiency in nD space (through splines, histograms, moments etc), but that's usually done when you'r

> I understand this argument if you're trying to model the efficiency in nD space (through splines, histograms, moments etc), but that's usually done when you're fitting to n variables, e.g. in an amplitude fit. If you just want the efficiency of a cut on the score from an MVA algorithm, I don't think it matters. What definitely matters is that the behaviour on simulation reproduces that of real signal as faithfully as possible. You might have a point there.