The Washington State Institute for Public Policy examined sex offenders who received or were statutorily eligible for SSOSA between January 1985 and June 1986. The report concluded that SSOSA was an effective sentencing alternative for eligible sex offenders because the community was at no greater risk, criminal justice professionals and treatment providers supported the alternative, and costs to State government were presumed to be lower. Sex offender recidivism was studied using a sample of all male sex offenders convicted in Washington during the January 1985-June 1986 period. Sex offender recidivism rates were 11 percent for those who received SSOSA, 14 percent for those statutorily eligible but who did not receive SSOSA, and 31 percent for those not eligible for SSOSA. A second study explored recidivism patterns of 1,373 adult sex offenders convicted between 1985 and 1991. Sex offender recidivism rates over the 7- year period were 12 percent for sex offenders, 3 percent for violent offenders, and 8 percent for other felony offenders. A third study compared recidivism patterns of sex offenders who received treatment during prison confinement with those of offenders who were imprisoned without treatment. The recidivism rate of the treatment group (11 percent) was slightly lower than the rate of the comparison group (12 percent), but the difference was not statistically significant. Supporting data are appended. Footnotes, tables, and figures