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The Simple Reason We Update Address Data

Written By Odell Jackson

June 8, 2023

When clients review their data proofs and/or data processing reports, they often ask why we’ve updated address data for recipients who haven’t moved. Our primary goal when processing a client’s mailing list is to optimize their ability to reach their intended recipients. We use two USPS tools to accomplish this: CASS and NCOA. 

When any of the final, processed addresses differ from the originally supplied data, our clients can be confident that any changes we make are USPS-directed and solely intended to enhance the deliverability of their mailings.

There are several reasons why we may need to change an address during data processing. Let’s look at some of the common reasons.


When we prepare a client’s list for mailing, one of the first steps we take is to process the data through the USPS CASS (Coding Accuracy Support System). CASS is a service provided by the USPS that checks and corrects address errors, appends missing information like ZIP codes, and validates addresses to ensure that they exist in the USPS database as deliverable addresses. CASS can fix some minor typos, abbreviate the street suffix (Road to Rd, Avenue to Ave, etc.), and will generally adjust the delivery address to meet USPS preferred standards. 

CASS also incorporates two other services: LACSlink, which updates obsolete “Rural Route” address formats to new 911 Emergency System compatible addresses, and SuiteLink, which applies known current suite information to business addresses.


Our next step is to submit the client’s address file to the USPS NCOA (National Change of Address) system. NCOA will compare the supplied address to the national database of all residential and business customers that have filed a Change of Address request with the Post Office. When the system identifies a match, it returns the new address. 

Sometimes an individual or business may supply the USPS with a new address that can’t be verified as valid. In those cases, the NCOA system will return the original address with coding to indicate that the recipient has moved but the new address is invalid.

In summary, we may change or update a supplied address as part of our data processing due to:

  • CASS correcting typos and updating other address elements to the USPS preferred format.
  • LACSlink updating older formatted addresses like rural routes and highway routes.
  • SuiteLink appending known suite information to a business address.
  • NCOA providing updated addresses for individuals or businesses who have moved and filed a verifiable Change of Address request.

We use these USPS tools when processing data to achieve the best postage rates for our clients while ensuring that their mailed communications deliver as intended. To qualify for the best presorted postage rates, the Post Office may require NCOA processing. NCOA reduces the number of UAA (undeliverable as addressed) mail pieces, and the USPS passes some of the resulting cost savings on to postal customers through lower postage rates.

When in doubt, the USPS provides an online tool that allows you to verify whether a given address is recognized as a deliverable address. The ZIP Code by Address Lookup Tool allows you to input a street address, city, state, and ZIP code. If the address is valid, the system will return the USPS preferred format for the address as well as a full nine digit ZIP code. This can be especially helpful when verifying institutional addresses such as universities and municipal locations. Many of those organizations no longer receive or accept mail at their physical street address and have instructed the USPS to only deliver to a PO Box, mailroom, or mail receiving facility.