The acronym CASS stands for Coding Accuracy Support System. The United States Postal Service, or USPS, offers CASS certification to businesses in order to facilitate the automation and accuracy of the mailing process.
CASS certification allows business mailers to help the USPS process their mail. They receive a worksharing discount on postage in return for their assistance.
CASS certification became available in the late 1980s as an extension of the USPS' worksharing discount program, which began in 1983.
The CASS certification system uses software that matches entries in a business' address list with entries in the USPS national database via the AMS (Address Matching System) CD-ROM.
The CASS matching process verifies that addresses are either correct and deliverable or incorrect and undeliverable. The USPS informs businesses of errors. Business mailing lists must undergo CASS certification every six months, and businesses must update the software every year.
CASS certification enables businesses to save approximately five cents postage on each piece of mail as of January 2006. It also improves the ability of mail carriers to deliver mail accurately and in a timely manner.
Businesses that do not seek CASS certification for their mailing lists must pay standard First Class postage rates.