The Coding Accuracy Support System (CASS) enables the USPS to evaluate the accuracy of software that corrects and matches street addresses. 1
A service provider that meets all of the stringent USPS accuracy requirements is CASS-Certified™.2
Why CASS-Certified™ vendors matter
Once an address has been cleaned up, standardized, and verified as deliverable, you can be nearly 100% sure that it will be delivered as expected.3
- CASS™ System, USPS <http://zip4.usps.com/ncsc/addressservices/certprograms/cass.htm>
- Coding Accuracy Support System, Wikipedia <http://en.wikipedia.org/wiki/Coding_Accuracy_Support_System>
- Of course things like meteorites, volcanoes, or a loose pack of rabid dogs can still cause delays to postal delivery. But at least you can say you did your best.