Chapters 10 & 11 (Richards text) CHANGING CRITERION Designs in Single-Subject Research

1. Chapters 10 & 11 (Richards text)CHANGING CRITERIONDesigns in Single-Subject Research Ps534 Dr. Ken Reeve Caldwell College Graduate Programs in ABA

2. Review: Single-Case Experimental Designs Issues For each design we will ask the following: • Does the design allow us to see a change in DV (without regard to whether it was caused by the IV)? YES • Does the design allow us to infer a functional relationship between IV and DV? YES • Why does it allows this? WE’LL FIND OUT • What threats to internal validity (confounds) does the design control for? • What ethical issues are important to know about using a particular design?

3. CHANGING CRITERION Designs Main Purpose: We examine the effects of one IV (treatments) on a SINGLE DV (target behavior) Specifics: • Usually used with a target behavior the person already has in their repertoire • And we want to dramatically increase or decrease the target behavior (rate, duration, frequency, % correct, magnitude) • And it is a behavior that is usually very difficult to change a great deal all at once (studying, smoking, cursing, over-spending) • Frequently used in self-management interventions

4. How To Do CC Designs • Begin with single participant (each participant is a SEPARATE experiment and serves as his or her own control like in a withdrawal design) • MUST take baseline to demonstrate experimental control (phase A) • Prior to initial treatment step (phase B1), you must determine two different criteria: • a) criterion to move to next treatment step and • b) final goal criterion • Learner must reach step criterion for at least 2/3 occasions before next treatment step (phase B2) is implemented • Continue on with treatment phases B3…BX • Stop when final goal criterion is reached

5. Sample CC design Phase A B1 B2 B3 B4 B5

6. Issues Using CC Designs • You should vary each treatment phase to control for confound of person simply changing behavior when a certain number of days goes by (as opposed to the person’s behavior actually being controlled by the changes in response requirements • Longer phases are needed for slow-to-change behaviors • Shorter phases are okay for quick-to-change behaviors • More…

7. Issues Using CC Designs • How much of a step increase in response requirements is desirable? • Clinically, the quicker you get to the goal the better BUT if you step up too fast then it is too difficult to succeed so better to be conservative • There are formulas to determine the steps but there are no studies demonstrating what step size is most desirable (thesis or dissertation anyone?) • Usually the first step in treatment is the average of the baseline responding (or slightly higher than the average)

8. “Reversals” in CC designs (step down) • To increase internal validity (demonstration of functional relationship), you can step down the requirements to see if behavior drops • This is a GREAT control for maturation & practice effects, in particular

9. “Reversals” in CC designs (back to baseline) Not shown in this graph but imagine that the “reversals” are return to baseline • Experimentally, it is even better if you reverse back to baseline instead of just stepping down response requirement (assuming behavior will drop a lot) • Clinically, though, this may not be as ethical

10. Design a study using CC Design • Question: You wish to decrease the frequency of cigarette smoking in an adult group home resident who currently smokes 60 cigarettes a day and has been doing it for 20 years. • The resident already uses a token motivational system to earn access to leisure activities • How would you do it?

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