This presentation describes the use of asymmetric confidence limits to test for mediation when the direct effect was not significant and effect suppression was present.

1. Assessing Mediation in HIV Intervention Studies Felicia Hardnett The findings and conclusions in this presentation are those of the author(s) and do not necessarily represent the views of the Centers for Disease Control and Prevention.

3. What is Mediation?

6. Single Mediator Model Indirect effect: αβ Direct Effect: τ ’ Total Effect: αβ + τ ’ τ ’ Intervention Mediator Outcome α β

15. Mediation in HIV Intervention Studies

18. How is Mediation Measured?

19. Baron and Kenny (1986) τ ’ Intervention Mediator Outcome α β

20. Baron and Kenny (1986) Intervention Mediator Outcome α β τ ’

21. Baron and Kenny (1986) τ ’ Intervention Mediator Outcome α β

22. Baron and Kenny (1986) τ ’ Intervention Mediator Outcome α β

23. Baron and Kenny (1986) τ ’ Intervention Mediator Outcome α β

27. Product of Coefficients ( αβ ) Indirect effect: αβ Direct Effect: τ ’ Total Effect: αβ + τ ’ τ ’ Intervention Mediator Outcome α β

35. Questions?