From a public health perspective, strategies for addressing children's harmful sexual behaviors often focus on secondary or tertiary prevention rather than primary prevention. Prevention efforts have also typically focused on preventing victimization by adults; yet a high proportion of child sexual abuse is perpetrated by other children and young people. We systematically reviewed the research on primary prevention strategies for harmful sexual behaviors in children and young people. We searched 6 databases, extracted data relating to program setting and focus, participant demographics, outcomes measured, and program success., We conducted a narrative synthesis in line with the SwiM guidelines (Popay et al., c2006), and conducted individual quality assessments of the included studies. 20 studies met our inclusion criteria. Primary prevention strategies were typically implemented in schools with primary/elementary, middle, and high school aged students. All programs included harmful sexual behavior within broader abuse prevention programs. Program effects were mixed. Primary-level prevention of harmful sexual behavior is typically addressed through broader sexual violence prevention programs. Around three-quarters of studies evaluating program efficacy found improvements in the outcomes measured, including some behavioral outcomes. Important to program success was who facilitated the program, as well as students' feeling of school connections. We found no evaluations of programs aimed at reducing harmful sexual behavior perpetrated online. Important new directions in program development will be to: (i) address the needs of younger children, as well as youth with disabilities, neurocognitive differences, and who are gender or sexually diverse; (ii) introduce and reinforce the concept that sexual behaviors exist on a continuum from healthy to harmful, providing clear examples; (iii) focus on both preventing perpetration and victimization; (iv) address strategies to support safe environments—in homes, organizations, communities, and online; and (e) identify essential elements for successful harmful sexual behavior prevention and align prevention programs with these features. • Harmful sexual behavior interventions at the primary prevention level are typically part of broader programs. • Most studies identified significant improvements across program outcomes measured. • Who delivered the program and school connection were important factors for success. • There are no studies evaluating the effect of online-facilitated harmful sexual behavior.

Our paper reports on a systematic review of crime concentration studies over the last 35 years. We identify 47 papers that report on crime concentrations at a micro geographic unit of analysis. These papers produced 49 estimates of general crime concentration for crime incidents at streets segments for a specific cumulative proportion of crime. The median concentration for these estimates is 50 % of crime found at 4.5 % of streets, and 25 % of crime at 1.25 % of streets. The bandwidth for 50 % crime concentration is 9.3 % (1.7–11.0 %), and for 25 % crime concentration 3.0 % (0.4–3.4 %). Using the interquartile range to exclude outliers, we found a bandwidth of 2.5 % (3.2–5.7 %) for 50 % of crime, and 1.4 % (0.8–2.2 %) for 25 % of crime. Crime concentration was generally stronger for specific types of crime, and bandwidths of concentration were generally smaller. Using alternative measures of crime and different micro geographies produces similar conclusions regarding strong crime concentration at place with narrow bandwidths. Our review shows that a general framework of a law of crime concentration applies across a large number of cities across many regions around the world.