The law is enacted and enforced on a state-by-state basis. In Colorado, an offender must re-register when moving to a new address, changing their legal name, employment, volunteer activity, identifying information used online or enrollment status at a post-secondary educational institution. Unlike physical castration, it is reversible by stopping the medication. Such programs are effective in lowering recidivism by 15—18 percent. Those on parole or probation may be subject to restrictions not applicable to other parolees or probationers. Individuals convicted of petty crimes not covered by the AWA are still liable to abide by the previous regulations denoting them as a sex offender or habitual sex offender, sexual predator, sexually violent sexual predator, or child-victim offender. Two such approaches from this line of research have promise. The offender must act upon the notification within five business days of receipt. In the United States, the United Kingdom , and other countries, a convicted sex offender is often required to register with the respective jurisdiction's sex offender registry. A web-based registration list may be found on county websites, which identifies adult convicted sex offenders who are sexually-violent predators convicted of felony sexual acts, crimes of violence or failure to register as required. An offender's email addresses, chat room IDs and instant-messaging aliases must be surrendered to authorities. Sexual offenders are sometimes classified by level. Therapies and treatment Behavior modification programs have been shown to reduce recidivism in sex offenders. Within three years of release, 2. Some areas only require sex offenders to register their name, while others hold restrictions on residency. Some states such as Arkansas, Illinois, Washington and Idaho do not require sex offenders to move from their residences if a forbidden facility is built or a law is enacted after the offender takes up residency. However, they could reasonably expect to be successful in applying for a position in an office where contact with children is unlikely.