For the Medicaid and Food Stamp programs, the USDHHS and the USDA are mandated to subsample the cases reviewed and submitted by ARU from the Department's random sample. If a difference is noted by a federal agency, ARU is notified in writing and has opportunity to present more information or contest the finding. Very stringent time frames for response to federal differences cases are imposed by Federal QC policy. By proceeding according to Federal QC policies, the case can ultimately end up being arbitrated at the regional and national levels. The final decision is fixed by the national level arbitration system of each federal agency.