The report is based on a year-long study that involved eight site visits to repositories of criminal history records as well as an examination of State and Federal statutory and case laws. Sealing is a prohibition on dissemination except to the record's subject or pursuant to a court order, whereas purging is destruction of a record or elimination of the name on the record. A sealing or purging order completely prohibits or drastically limits the use of a criminal history record by law enforcement officials or other persons. The rationale and constitutional basis for sealing or purging and applicable State and Federal statutory laws are discussed. The model standards outlined address key issues raised by sealing and purging, such as definitions, authority to set standards, scope of the standards' coverage, and substantive criteria for entitlement to a sealing order and implementation mechanisms. The model standards also take into account the effect of a sealing or purging order on other criminal justice agencies, rights of criminal record subjects to obtain a sealing or purging order and to deny the events covered by such orders, and the right of criminal justice agencies to unseal records. Considerations regarding implementation of the standards are noted. A glossary, 21 references, and 85 footnotes are supplied.