Background:
“Sister to Sister” was an intervention for African American women that obtained significant effects on self-reported behavior and STI incidence (Jemmott, Jemmott & O'Leary, 2006).

Objective:
The present analyses were conducted to identify which theory-based factors that were addressed in the intervention accounted for its success.

Method:
A mediation analysis was conducted with condom use at last sex, self-reported 12 months after the intervention, as the outcome. Mediators, also measured at 12-month follow-up, were derived from Social Cognitive Theory. They were: condom use knowledge; hedonistic condom beliefs; expected partner reactions to condom requests; partner approval of condom use; self-efficacy for impulse control; self-efficacy for carrying condoms; and self-efficacy to achieve consistent condom use with partner.

Result:
The intervention improved all potential mediators except condom use knowledge (p = .15); hedonistic beliefs (p = .08); and impulse control (p = .20). When the mediators were tested one at a time, significant mediation was observed for expected partner reaction; partner approval of condoms; self-efficacy for condom carrying; and self-efficacy for condom use. When they were entered into a multivariate mediation analysis, however, only self-efficacy for condom use was significant (p < .001).

Conclusion:
Many have described women's ability to protect themselves from STI as being minimal because they are at the mercy of their male partners, who control male condom use. While these analyses show that partner reactions and condom approval do matter for women, ultimately it is their own self-efficacy that matters most. People whose self-efficacy is strong exert more effort and are more likely to persist in their attempts to achieve their goal. The increases in self-efficacy that the skill-building intervention achieved are clearly the primary reason for the intervention's success.

Implications:
Successful prevention interventions for women provide skill-building for condom negotiation and use, and work because they increase womens' self-efficacy to use condoms consistently.