CASS Certication

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Coding Accuracy Support System (CASS)


The Coding Accuracy Support System (CASS) improves the accuracy of carrier route, five-digit ZIP, ZIP+4, and delivery point codes that appear on mailpieces. CASS is offered to all mailers, service bureaus, and software vendors who want to evaluate their address-matching software and improve the quality of their ZIP+4, CRIS, and five-digit coding accuracy. This process is graded by the United States Postal Service's National Customer Support Center (NCSC), and the results returned to mailers in order to provide useful diagnostics for correcting deficiencies. CASS enables the Postal Service to evaluate the accuracy of address-matching software programs in three areas: (1) ZIP+4 delivery point coding, (2) carrier route coding, and (3) five-digit coding. CASS allows vendors/mailers the opportunity to test their address-matching software packages and, after achieving a certain percentage of compliance, to be certified by the Postal Service. CASS does not measure the accuracy of ZIP+4 delivery point, five-digit ZIP, or carrier route codes in a mailer's existing files. CASS enables mailers to measure and diagnose internally written, commercially-available, address-matching software packages. The effectiveness of service bureaus' matching software can also be measured. There are two stages in the CASS process: Stage I, which is optional, and Stage II, which is required for certification.


STAGE I-A Test With Answers CASS Stage I enables businesses with address-matching software to test their software against test addresses provided by the Postal Service. The CASS file contains approximately 100,000 test addresses extracted from the City State and ZIP+4 Files with samples of all types of addressing used around the country. (Some test addresses have been changed for test purposes, and not all records have valid ZIP+4 Codes or valid addresses.) Customers can evaluate the accuracy of their address-matching software by applying the correct carrier route, five-digit, and ZIP+4 Codes and by comparing the applied codes with the correct codes provided by the Postal Service.


STAGE II-A Test Without Answers CASS Stage II also contains approximately 100,000 test addresses that are extracted and presented in the same makeup and mixture as Stage I-only no answers are provided. Customers use their address-matching software to apply the correct codes. Match rates using CASS-certified software vary greatly depending on address hygiene, the quality of addresses used, and the timeliness of the customer database update applications. An address with an incorrect ZIP+4 Code, carrier route code, five-digit ZIP Code, or an address with no ZIP+4 Code can contribute to delays in processing mail. To be CASS-certified, participants must pass with a minimum score of 96% for ZIP+4, 100% for delivery point coding, and 98% for carrier route and five-digit. CASS certification is valid for six months. Certified vendors are published periodically in postal documents.