1. EVAL 6970: Meta-Analysis Subgroup Analysis Dr. Chris L. S. Coryn Kristin A. Hobson Fall 2013

2. Agenda Subgroup analyses – In-class activity

3. Subgroup Analyses

5. ModelMethod 1Method 2Method 3 Fixed-effect 123 456 789

6. Fixed-Effect Model within Subgroups: Method 1

7. The difference between the two effects is Which is tested as Where

8. Fixed-Effect Model within Subgroups: Method 1 Where For a two-tailed test =(1-(NORMDIST(ABS(Z))))*2

9. Fixed-Effect Model within Subgroups: Method 1

10. Fixed-Effect Model within Subgroups: Method 2

13. A 8.431640.0770 B 4.542940.3375 Within 12.974580.1127 Between 13.462610.0002 Total 26.437190.0017

14. Fixed-Effect Model within Subgroups: Method 2 Variance components

15. Fixed-Effect Model within Subgroups: Method 3

16. Use Total between

17. Magnitude of Subgroup Differences With The 95% confidence interval is Where

22. A 8.43164269.8413 B 4.54294241.6667 Total 12.97458511.5079

23. Use A and B and Total within

26. Proportion of Explained Variance

30. Variance Explained by Subgroup Membership

31. Summary Effects in Subgroup Analyses Depends on questions and the nature of data If question is one of superiority, best not to report a summary effect across subgroups If question is one of equivalence, a summary effect across subgroups may or may not be warranted Most important are substantive implications and what summary effect represents

32. Models for Subgroup Analyses Three models – Fixed-effect analysis: Fixed-effect model within and across subgroups – Mixed-effect analysis: Random-effects model within subgroups and fixed-effect model across subgroups (generally recommended model) – Fully random-effects analysis: Random- effects model within and across subgroups

33. Today’s In-Class Activity