[9] According to Association for the Treatment of Sexual Abusers, the states (e.g. Minnesota, Washington) where community notification has indicated some effectiveness employ empirically derived sex offender risk assessment procedures and apply public notification only on high risk offenders.
[11] Some policies — especially residency restrictions and community notification — may adversely impact on public safety due to the obstacles they create to successful reintegration of an offender.
[9] Prescott and Rockoff (2011) found that Sex Offender Registration policies in the United States were effective at reducing crime by providing general deterrence.
The study found that non public registration policies were effective in reducing sex crime arrests due to enhanced police monitoring of existing offenders.
[citation needed] One research method employed to assess the effectiveness of SORN for adult sexual offenders is interrupted time series analysis, which essentially examines an outcome of interest using many observations before and after the implementation of a specific intervention.
[9] A study done in University of Chicago Law School compared data on over 9,000 sex offenders released from prison in 1994.
[15][9] A study conducted in University of Michigan Law School in 2008, distinguishing between the effects of registration (police- only) and community notification (public registries), analyzed Uniform Crime Reports (UCR) data from 15 states over more than 10 years.
The study found evidence that police-only registration laws reduce the frequency of reported sex offenses, particularly when the number of registrants is large but making the registry information available to the broader public may "backfire", leading to higher overall rates of sex crime.
An average-size registry was estimated to decrease crime by approximately 1.21 sex offenses per 10,000 people, which correspond to 13 percent reduction on average.
Making the registration information public was found to increase the number of sex offenses by more than 1.57 percent.
Based on the varied findings, the authors concluded there was no systematic influence of SORN on the rate of reported rape.
[17][9] A number of state studies did not find evidence that SORN implementation positively impacted the rate of sexual offending or recidivism.
In the South Carolina study that did not find evidence of a positive SORN effect, recidivism was examined in the context of registration status for 6,064 male offenders convicted of at least one sex crime in that state between 1990 and 2004.
[18][9] Another state study taking place in New York analyzed sex crime, assault, robbery, burglary, and larceny arrests from 1986 through 2006.
To examine the relationship between community notification and recidivism, the Minnesota Department of Corrections conducted a study comparing differences between three groups.
[7] The authors concluded that these results suggest a community notification system based on tiered risk-management has an effect of reducing recidivism, although they noted that part of the effect might arise from heightened penalties and post-release supervision, improved treatment, or unmeasured historical factors unique to the 1990-1996 period.
[citation needed] The vast majority of those states require registration and public notification for juveniles transferred for trial and convicted as an adult.