A systematic review by the Campbell published in 2009 identified 10 randomized impact evaluations involving a total of 1,527 women participating in support and empowerment programs [1]. The evaluations have shown that longer, more intensive programs lasting more than 12 hours work to reduce the incidence of violence against women. However, the authors point out that, in general, the evidence is inconclusive. Although most studies have shown improvements in one or more outcomes, the studies identified were too diverse for their results to be synthesized, and therefore it was not possible to detect a clear effect of those interventions.
An update to this systematic review published in 2016 revealed mixed evidence on the impact on domestic violence. Overall, there was no impact on physical violence (although some individual studies did identify impacts, particularly for pregnant women) nor on sexual violence. With respect to emotional abuse, one of the studies reported a positive effect (reduction in prevalence) [2].
On the Crime Solutions platform, four meta-analyses evaluated 47 studies on services for female victims of domestic violence. Psychotherapeutic programs for victims of sexual violence are effective to reduce the symptoms of Post-Traumatic Stress Disorder (PTSD) [3][4].