“…"What is the relative efficacy of various procedures in treating the same problem behavior?" Although these questions certainly have merit, their focus is limited to technical application per se without concern for discovery of the variables that control behavior under natural conditions (Morris, 1991 (Iwata, Vollmer, Zarcone, & Rodgers, 1993). A number of studies have now shown that the inefficacy ofsome nonintrusive treatments may be due to the mismatch between operant function and treatment (Durand & Carr, 1987;Repp, Felce, & Barton, 1988) or to a change in operant function over time (Lerman, Iwata, Smith, Zarcone, & Vollmer, 1994) rather than an indication of the need for more intrusive procedures.…”