Ps534 Dr. Ken Reeve Caldwell College Graduate Programs in ABA

1. Chapters 5-6 (Richards text)Chapter 8 (first half) (Cooper text) – Reversal (a/k/a Withdrawal) Designs in Single-Subject Research Ps534 Dr. Ken Reeve Caldwell College Graduate Programs in ABA

2. Single-Case Experimental Designs • Traditionally called single-subject designs • Now referred to as single-case and single-participant designs • Historical tradition – Behavior Analysis • Techniques and logic applied to other research areas • If done well, is a perfectly valid research design

3. Single-Case Experimental Designs: Terminology • AB = baseline → intervention • ABA = baseline → intervention → baseline • ABAB = baseline → intervention → baseline → intervention • BAB = intervention → baseline → intervention

4. 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)? • Does the design allow us to infer a functional relationship between IV and DV? Why does it allows this? • What threats to internal validity (confounds) does the design control for? • What ethical issues are important to know about using a particular design?

5. Single-Case Experimental Designs: The AB “design”

6. Single-Case Experimental Designs: The AB “design” • 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? NO. Why DOESN’T it allows this? • What threats to internal validity (confounds) does the design control for? NONE • Ethical issues?

7. The ABA Withdrawal (Reversal)

8. The ABA Withdrawal (Reversal) • 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? IF ONLY IV IS MANIPULATED, THEN NOT LIKELY ANYTHING BUT IV CAUSED CHANGES IN DV • What threats to internal validity (confounds) does the design control for? MATURATION & HISTORY • Ethical issues? BETTER BECAUSE ITENDS ON TREATMENT

9. The ABAB Withdrawal (Repeated Reversal)

10. The ABAB Withdrawal (Repeated Reversal) • Does the design allow us to see a change in DV (without regard to whether it was caused by the IV)? DUH • Does the design allow us to infer a functional relationship between IV and DV? YES, EVEN BETTER THAN THE ABA DESIGN. • Why DOES it allows this? IF ONLY IV IS MANIPULATED, THEN NOT LIKELY ANYTHING BUT IV CAUSED CHANGES IN DV • What threats to internal validity (confounds) does the design control for? MATURATION & HISTORY • Ethical issues? ENDS ON BASELINE

11. The ABABABAB Withdrawal (Repeated Reversal)

12. When to Use the ABAB Withdrawal (Repeated Reversal) • When you need to observe a functional relationship (otherwise you can use the AB design) • When the effects of IV (intervention) do not “remain” in the DV • When ethics allow this design. If it is NOT ethical to remove treatment, then don’t use a withdrawal design

13. Adaptations of Withdrawal designs: BAB design • Better from an ethical standpoint because client or learner gets intervention right away and ends on treatment • Worse than ABA design from a “control” standpoint because we don’t know pre-intervention levels (BAB has slightly lower internal validity than ABA)

14. Adaptations of Withdrawal designs: ABC (Changing Conditions) “design” • Used when treatment B tanks and you switch to a new treatment C • Introduces an unwanted possible confound of order/sequence effects (Maybe C only works if it follows B!) • Has poor internal validity but is very similar to how we provide treatment in “real world.” • Can be improved if we use…(see next)>>

15. Adaptations of Withdrawal designs: ABAC (“Multiple Treatments”) design • Allows better chance to see functional relationship • Has better internal validity • Can be improved even more if we use ABACA (with added C phase)

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