  In this letter, we propose a novel statistical method to measure which system
is better suited to probe small deviations from the usual quantum behavior.
Such deviations are motivated by a number of theoretical and phenomenological
motivations, and various systems have been proposed to test them. We propose
that measuring deviations from quantum mechanics for a system would be easier
if it has a higher Kullback Leibler divergence. We show this explicitly for a
nonlocal Schrodinger equation and argue that it will hold for any modification
to standard quantum behaviour. Thus, the results of this letter can be used to
classify a wide range of theoretical and phenomenological models.
