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Validating an address with CASS and DPV data

A lot goes into confirming that an address is valid. For the United States Postal Service (USPS), there are several pieces of information needed to verify an address. When you use address validation software, it checks the information entered against USPS’s database and requirements. A couple of terms to know when it comes to address validation are CASS and DPV. The Coding Accuracy Support System (CASS) is a certification process used by USPS to evaluate the accuracy of address correction/matching software. Delivery Point Validation (DPV), which is one of the USPS-sourced files included in CASS data, is used to check the status of a specific address within the United States.

CASS Certification

Using CASS-certified software to evaluate addresses can qualify mailers for discounted rates through the USPS. As a CASS-certified vendor, Experian Data Quality’s products cleanse, verify, and standardize addresses before matching against CASS data, which helps our customers receive mailing discounts.

CASS data is comprised of the following USPS sourced products/files:

  • 5-digit ZIP coding
    • Zone Improvement Plan (ZIP) code (length: 5 digits) - Postal code system used by the United States Postal Service.
  • ZIP + 4
    • Extension of a ZIP code which determines a more precise location within the ZIP. (Length: 4 bytes)
  • Delivery point coding (DPC)
    • Delivery Point Code (length: 2 bytes). This field contains the last two digits of the house/box number, or if the match is made to a highrise record, the secondary unit number representing the delivery point information to form the 11-digit or delivery point barcode (DPBC). Possible values: “00” through “99” or spaces.
  • Carrier route coding
    • Code assigned by the USPS to a group of addresses to aid mail delivery within a ZIP code. Consists of a carrier route type and carrier route code (Length: 4 bytes). For example, “C001”.
  • LACSLink
    • Locatable Address Conversion System is a dataset provided to allow addresses that have been converted due to USPS changes or for 911 emergency systems to be linked with their new address.
  • SuiteLink
    • The SuiteLink dataset returns information about changes made to an address following comparison with the USPS SuiteLink data. A 'Y' indicates a SuiteLink match, where secondary information is automatically appended to the output address. An ‘N’ indicates no match. A blank indicates that no lookup was performed.
  • eLOT
    • Extended LOT allows mailers to sort their mailings in approximate carrier-casing sequence.

Once data has been processed through a CASS-certified product, a CASS Summary Report can be generated. This report contains information about the condition of the original addresses and how the addresses have changed since cleaning. It is required where USPS mailing discounts are sought.


DPV is another dataset used for address verification. The actual process for DPV uses the ZIP+4 to validate whether the address has verifiable primary and verifiable secondary address information. This is different from standard address validation because its purpose is to tell the user whether the address exists—not just that it’s in the postal database.

Experian Data Quality offers a DPV Confirmation Indicator in our address validation services which allows customers to verify that mail has been delivered to the address entered within the last two months. This is important as packages shipped to bad addresses can lead to several losses for the business: returned mail and postage costs, time spent contacting the customer to alert them of delays, or downturns in customer satisfaction. For marketing campaigns, there is the loss of postage and the potential loss of future or repeat customers because of poor communication or brand perception. By validating an address against DPV data, you can avoid the costs associated with shipping to inaccurate addresses.

Using CASS-certified software, including DPV confirmation, offers your business considerable cost savings for mailing and shipping. When you use a CASS-certified address verification software, you not only qualify for mailing discounts through the USPS, but you also significantly reduce costs for returned mail or poor customer experiences by confirming the accuracy of the addresses to which you send.