Types of Experimental Designs (Educational research)

2. Types of Experimental Designs(Educational research) • True Experimental • Quasi-Experimental

3. Types of Experimental Designs • Simple True Experimental • Quasi-Experimental

4. Types • Randomized posttest control group design • Randomized pretest-posttest control group design

5. Randomized posttest control group design R T Post R C Post

6. Randomized pretest-posttest control group design R Pre T Post R Pre C Post • Makes it possible to ascertain that groups were equivalent at the beginning of the study. • Not necessary if: • Randomization was used • Large sample size

7. Solomon four-group design R Pre T Post R Pre C Post R T Post R C Post Four groups are formed by random assignment ( R ) of participants, two groups are pretested ( O ) and two are not, one pretested and one unpretested group receive the experimental treatments ( X1, X2 ), each group is administered a posttest on the dependent variable, and posttest scores are compared to determine effectiveness of treatments

8. Types of Experimental Designs • Simple True Experimental • Quasi-Experimental

9. Characteristics of True Designs • Manipulation (treatment) • Randomization • Control group • Less control • More real-world • Program evaluation

10. Quasi-experimental Designs • One group posttest-only design • One group pretest-posttest design • Non-equivalent control group design • Non-equivalent control group pretest-posttest design • Time series

11. Quasi-experimental Designs • One group posttest-only design • One group pretest-posttest design • Non-equivalent control group design • Non-equivalent control group pretest-posttest design • Time series

12. Randomized posttest control only design R T Post R C Post

13. One group posttest-only design (One shot study) T Post No control of IV threats Use?

14. Quasi-experimental Designs • One shot study • One group pretest-posttest design • Non-equivalent control group design • Non-equivalent control group pretest-posttest design • Time series

15. Randomized pretest-posttest control group design R Pre T Post R Pre C Post

16. One group pretest-posttest design Pre T Post • History • Maturation • Testing • Instrumentation • Regression Use control group

17. Quasi-experimental Designs • One shot study • One group pretest-posttest design • Non-equivalent control group design • Non-equivalent control group pretest-posttest design • Time series

18. Randomized posttest control group design R T Post R C Post

19. Non-equivalent control group design (Static group comparison design) T Post C Post • Selection bias

20. Quasi-experimental Designs • One shot study • One group pretest-posttest design • Non-equivalent control group design • Non-equivalent control group pretest-posttest design • Time series

21. Randomized pretest-posttest control group design R Pre T Post R Pre C Post

22. Non-equivalent control group pretest-posttest design Pre T Post Pre C Post • Can check selection bias

23. Quasi-experimental Designs • One shot study • One group pretest-posttest design • Non-equivalent control group design • Non-equivalent control group pretest-posttest design • Time series

24. Time series Pre Pre Pre Pre T Post Post Post Post …a single group is pretested ( O ) repeatedly until pretest scores are stable, exposed to a treatment ( X ) and, then, is repeatedly posttested ( O )