'''CASSCoding Accuracy Support System''' ('''Coding Accuracy Support SystemCASS''') enables the [[United States Postal Service]] to evaluate the [[accuracy]] of [[software]] that cleanscorrects and matches [[street address]]es. CASS [[certification]] is offered to all mailers, [[service bureau]]s, and software [[vendor]]s that would like the [[USPS]] to [[evaluate]] the [[quality]] of their address-matching software and improve the [[accuracy]] of their [[ZIP Code|ZIP]]+4, [[carrier route]], and five-digit coding.
For software vendors and service bureaus, CASS Certification must be renewed annually with the USPS to meet current CASS Certification cycle requirements.
CASS Certified products are listed in USPS literature and on its web site. CASS software will correct and standardize addresses. It will also add missing address information, such as ZIP codes, cities, and [[state (US)|state]]s, to ensure the address is complete. Starting with 2007 Cycle L, CASS software will also perform [[delivery point]] [[Data validation|validation]] to verify whether or not an address is a deliverable address and accesscheck against the USPS [[Locatable Address Conversion System]] to update addresses that have been renamed or renumbered. Cycle L also requires that the address be confirmed with the [[Delivery Point Validation]] before adding a +4 code to the ZIP code.
A correct address in turn saves the Postal Service time, money and manpower by reducing the volume of 1) non-deliverable mail; 2) unsorted mail; 3) mail that is deliverable, but requires extra effort to determine the proper ___location to deliver it to.<ref>{{cite web | url = http://ribbs.usps.gov/files/CASS/CASS%5FCYCLE%5FL/CASS_CERT_REQ_MAILERS_GUIDE.PDF | title = CASS Certification Requirements, A Mailer's Guide | publisher = United States Postal Service | accessdate = 2007-07-27 | date = 2007-06-26 }}</ref>. Mailers who use CASS software to check the addresses of their mailing may be able to qualify for [[discounts and allowances|discount]]ed postage rates from the USPS.
An example of what CASS software will correct in an address:
