The NCOA process takes the mailing list and programmatically examines each element of the address. The program attempts to verify or correct the ZIP Code; standardize the format for address, city, and state names; and append ZIP+4 Codes, carrier route codes, and delivery point barcode information to the mailing list addresses. Once this standardization process is completed, the entire list is matched against the NCOA database. When a match from the list is made to an NCOA name and address, the new address information is returned to the list holder.

The NCOA database consists of address information for individuals, families, and businesses that have moved within the past 36 months. The names and addresses are compiled from Change of Address orders presented to the Postal Service when a permanent move occurs. Temporary moves are not recorded on NCOA. The NCOA database contains 113 million permanent change of address records.

Since NCOA is used prior to a mailing, it greatly reduces undeliverable as addressed mail, which in turn reduces rehandling costs.

Note: The United States Postal Service requires addresses on all presorted and automated First Class to be updated within 180 days prior to the mailing date.