The differences between the authors of the Coleman report and their critics make clear why the effectiveness of schools will always remain controversial as long as inferential statistics are employed to determine it. Controversy is inevitable when measurement requires the satisfaction of assumptions antithetical to the teaching processes through which the effects of schools must be produced. Operant conditioning, by providing means for determining independent-variable effectiveness and dependent-variable effects in a single set of operants, lets such counterproductive assumptions be set aside. (Author)