1. CHAPTER OVERVIEW The Nonequivalent Control Group Design The Static Group Comparison Single-Subject Design Evaluating Single-Subject Designs

2. THE QUASI-EXPERIMENTAL METHOD No control over group assignment Useful when manipulation of variables is ethically, morally, or practically difficult

3. THE QUASI-EXPERIMENTAL METHOD Quasi-experimental research is post hoc research Internal validity is intermediate between pre-experimental and true experimental designs

4. THE NONEQUIVALENT CONTROL GROUP DESIGN Commonly used when random assignment is not possible Similar to pretest post-test control group design Selection bias is a threat to validity Participants Assigned to the Experimental Group PretestTreatmentPost-test Participants Assigned to the Control Group PretestNo TreatmentPost-test

5. THE STATIC GROUP COMPARISON No pretest Disadvantages –Questionable internal validity –Questionable external validity Experimental GroupTreatmentPost-test Control GroupNo TreatmentPost-test

6. SINGLE SUBJECT DESIGN Looks at cause and effect relationships in single individuals rather than in groups Common in behavioral analysis and special education Based on behavioral view of development Measure Behavior During Baseline Treatment Remove Treatment—Measure Behavior During Reversal

7. Measure Behavior During Baseline Treatment Remove Treatment—Measure Behavior During Reversal

8. AB designs (simple single subject) measure baseline and impose treatment ABA designs (reversal) remove treatment ABAB (alternating treatment designs) re-impose treatment

9. EVALUATING SINGLE SUBJECT DESIGNS Most have good internal validity External validity may be questionable