Child sexual abuse (CSA) impacts 15% of girls and 8% of boys worldwide, incurring high public costs and devastating consequences for survivors. US incidence rates have stagnated over the past 15 to 20 years, signaling a dire need for innovation in primary prevention. In 2024, the US Preventive Services Task Force reported that there is insufficient evidence for the effectiveness of child abuse preventive strategies, and none have shown decreases in incidence rates at the population level.

Objective  To test whether a coordinated, community-wide preventive intervention could significantly reduce population-level incidence rates of CSA.

Intervention  From 2018 through 2020, the state of Pennsylvania launched a 3-pronged CSA prevention intervention in 5 counties that included: (1) exposing 5% of the adult population (approximately 72 000) to online and in-person trainings with an accompanying countywide media campaign, (2) delivering a psychoeducation program to 100% of second-grade students (approximately 17 000), and (3) providing parent training to 100% of parents served by the child welfare system (approximately 300). Intervention counties were a priori matched to 1 of 5 control counties based on population size and preintervention CSA rates.

Results  Within 1 year of intervention launch, CSA reports were significantly reduced in intervention counties, as compared with control counties for both substantiated (average treatment of the treated [ATT] = −17.22; 95% CI, −34.15 to −4.20) and unsubstantiated reports (ATT = −36.04; 95% CI, −74.40 to −3.88).

Conclusions  In this evaluation of a place-based, coordinated, countywide intervention, reports of both substantiated and unsubstantiated CSA were shown to be significantly reduced at the population level.