Very true; or a result that just reflects a difference not neccessarily an improvement. One of the aspects of this theory says that any individual exposed to a test that requires a positive or negative reaction will always feel impelled to give a reaction of some sort whether or not there is a percieved difference. Statistically there is a low incidence of null outcomes due to this effect. So; even if you hear no discernable change you still feel as if there is a change in order to justify your participation in the test. Thats the pschycological payback.