What is the NCOA Database?

NCOA stands for National Change of Address. It is a database of 160+ million change-of-address records. Each record contains the name of the mover, the old “moved from” address, the new “moved to” address, or, if no address is available, a reason why.

NCOA Database

  • Compiled by the U.S. Postal Service from Change of Address cards.
  • Updated every week
  • Records remain on file for total of 48 months, counted from the effective date of the move.
  • Each record contains:
    • the name of the mover
    • the old “moved from” address
    • the new “moved to” address, or, if no address is available, a reason why
    • effective date of the move, and type of move (individual, family, or business/firm)
  • Three Types of Moves: Individual, Family, or Business.
    • Mover specifies the type of move on the Change of Address card. Moves made by Individuals account for roughly 47% of the file. Family moves represent another 47%. The remainder – roughly 6% of the file – are business moves. The move type plays an important role in NCOA matching requirements.
  • On average, the database contains the following move records:
    • Moves that have a forwardable “move to” address =             84.30% of the file
    • No address available, mover left no forwarding address =   2.85% of the file
    • No address available, PO Box was closed =                              2.65% of the file
    • No address available, moved to a foreign country =               0.20% of the file
      (Foreign addresses are not on the NCOA file)
  • On average, file includes 114 million records.
  • Permanent changes of address are added to the NCOA database; temporary moves aren’t included (Approximately 42 million people and businesses file a permanent Change of Address card each year.)
  • The new address supplied by the postal customer must be ZIP+4 codeable to qualify for addition to the NCOA file.

Getting a new address from NCOA:  What’s needed for a match

The matching requirements for NCOA are very conservative (tight). The U.S. Postal Service sets the matching requirements to guard against “matches” that move the wrong people. This protects you (and the Postal Service) from mis-delivered mail and irate customers.

The process looks for potential matches between your record and an NCOA record. In order to receive a new address, your record must meet the following conditions:

  • Your record must contain every address element that is present on the NCOA record (street, number, directional, prefix, suffix, or apartment information). If the NCOA address includes a “suite”, your address must also be a “suite” (“apartment” or “penthouse” will not match), and the suite numbers must match.
  • If the NCOA record is a family move, the surnames must match.
  • If the NCOA record is an individual move, both the surname and first name must match. If the first name is missing from either the NCOA record or the input record, no match is allowed and, in most cases, first names can’t be matched to first initials. When middle names are present, the names must match (middle initials are allowed to match to initials or to middle names). If either record has a genetic title (Jr., Sr., etc.) the other record must also have that same title.
  • Firm moves consist of a firm name and address. They do not contain any individual names. When your file includes records with both a contact (personal) name and a firm name, both names are compared with NCOA’s name field.


The rules for matching can be modified, at client request, to use only “individual” matching logic. “Family” (surname) logic would be suspended and all consumer moves would require a match of both surname and first name.

This “individual” matching gives you the assurance that change of address information pertains solely to the specific individual on your file. However, this also means that you’ll net fewer moves. If your person is part of a family move, and the Change of Address notice lists only the family surname or lists the first name of a family member other than your person, you won’t get any forwarding address.


NCOA’s “Nixie” option

The NCOA “Nixie” option is a tool that allows you to make better Mail/No Mail decisions. It is also known as N.E.S. or  Nixie Elimination Service). Some records on your file may be similar to “moved from” records on NCOA, but will not make an exact match. The “Nixie” matching process provides footnote codes indicating why an authorized NCOA match could not be made to the input address. These records may, in fact, be moves.

We can’t provide a new address, but we can tell you that these records may prove to be undeliverable. If the addressee has moved, your Standard (A) mailpieces won’t be delivered or forwarded or returned.

Rental or prospecting names should probably be treated like moves. You’ll probably want to suppress them from your mailing. When house file names are flagged as Possible Nixies, you’ll consider additional choices. The course you follow will depend upon the value of the name.

If you include the name in a mail plan, you may want to use “Forwarding Service Requested” or “Address Service Requested” endorsements. There’s a charge associated with this service, so contact your postal representative for information. Another alternative is to mail the name at First Class postage, which provides forwarding to the new address. If you mail the Possible Nixies, it’s a good idea to code them as a separate panel so you can track response.

When the name and address data isn’t an exact match, your record will receive one or more of the following NCOA Nixie Codes which will spell out the differences. 

  • The NCOA record that almost matched to your record will be identified by one of these codes:
    • R = Individual move was indicated on Change of Address form
    • S = Firm move was indicated on Change of Address form
    • T = Family move was indicated on Change of Address form
  • The outcome of the match step will be indicated:
    • A = A match to NCOA A new address is supplied whenever available.
    • B = NCOA Possible Nixie   The input record is similar to an NCOA record. A match couldn’t be made because of one or more NCOA rules.
    • C = No Match to NCOA   The input record isn’t similar to any NCOA master file record.
    • P = More than one NCOA record matched, so no match was allowed   NCOA file contains more than one possible match for the input record. NCOA doesn’t permit “pick one” logic, so a match can’t be made.
    • Y = Individual matching logic was used for all consumer moves (a client option)    Surnames match, other name components do not match.
  • Differences in the primary address:
    • D = No house number on the input record, but the NCOA record has a street and house number. House numbers must be exactly the same on both files.
    • M = One record has a box number, the other doesn’t. If both the input record and the NCOA record are Rural Route or Highway Contract Route addresses, and  one of the records has a box number, the other must also.
    • N = Street suffix or directionals are not equal. The suffix (ST, AVE, BLVD, etc.) and directional (N,S,E,W) must be identical, otherwise no match is permitted.
    • O = Street names are not equal    When the input address and NCOA address were compared, the street name was not similar enough to make an NCOA match.
  • Differences in the secondary address:
    NCOA rules require that if either record has an apartment number, the other record must contain a matching apartment number.
  • E – There is no apartment number on the NCOA file, but the input record has one.
  • Q = Unit designator values (apartment numbers) are not equal (the input apartment number isn’t the same as the NCOA file record.
  • U = The NCOA record contains an apartment number but the input record doesn’t have one
  • W = Last two digits of apartment number are transposed on one record  (for example 12456 = 12465).
  • X = Numbers are not equal or are missing when the NCOA record contains an “exceptional unit designator”.    Exceptional unit designators include “front”, “rear”, “side”, “basement”, “upper”, “lower”, “lobby”, and “office”. Usually, these don’t have any unit numbers. However, if the NCOA record includes a number, the input must also contain an equal value in order to make an NCOA match.


  • Differences in the firm names are indicated as a code I. The input record was compared to a firm record but a match could not be made.
  • Differences in surnames are coded F. The input surname is phonetically similar to the NCOA master file record. However, the degree of similarity isn’t close enough to meet NCOA requirements for a match.
  • Differences in title are coded H. A mismatched “seniority title” (such as JR., SR., I, II, or III) prevented a match. Either the input record has a title that is different from the title on the master file, or one of the records has a  title but the other has none.
  • When the matching rules for individual moves prevent a match:
    • G = First names are not equal. The NCOA record has the same surname, but the change of address is for an individual. First names must match on individual moves.
    • J = Input lacks a first name The input record has a surname, but no first name. The NCOA move record is for an individual, and a first name is required for matching.
    • K = Middle/secondary names are not equal   The surname and first names match, but there is also a middle name or initial present on both records, and they are not the same.
    • L = Gender is not equal.  Using the first name to determine gender, a comparison indicates that the gender is not the same on both records.
    • V = One record has a first name, the other has a first initial    Even if the initial letters match, NCOA matching rules for individual moves don’t permit this kind of match.

OUTPUT: What you can expect from NCOA processing

The Process

NCOA is a two-step process. Both steps provide you with good, useable information.

The first step parses and standardizes the record, and prepares the record for matching against the NCOA database. It also verifies or corrects the 5-digit ZIP Code, applies the carrier route and ZIP+4 codes and delivery point barcode information, and provides you with a Coding Accuracy Support System (CASS) Form 3553, needed to validate carrier route or automation rate mailings.

The second step, the match step, compares your record with the “moved from” records on the NCOA database. When a match is found, a new address can be supplied. Near-matches can be flagged by the NCOA Nixie process, which supplies codes to describe the differences between your record and the NCOA record.

The output file that you receive will include the following, as required by the U.S. Postal Service: your original address, accompanied by the standardized address (appended with ZIP+4 Code and Delivery Point Barcode data), plus a new address when a match has been found.

The Standardized Address

A standardized version of your address is used as input to NCOA. Standardization improves match rates against any postal file, and makes your addresses more readable by U.S.P.S. automated equipment.

The standardized address includes only those address elements that the Postal Service needs in order to deliver the mail. All other data is considered extraneous. Address records look like this:

  1. Primary Address (street address or rural route or PO Box)
  2. Secondary Address (apartment, suite, floor, etc.)
  3. Urbanization (only in Puerto Rico)
  4. City
  5. State
  6. ZIP+4 code

The Primary address may include these components: house number, pre-directional (N, S, E, W, etc.), street name, street suffix (ST, AVE, SQ, ETC.), and post-directional. Secondary addresses consist of the unit designator (APT, STE, RM, etc.) and the unit number.

Standardization compares the city name with a U.S. Postal Service table of  “official” place names (called the City/State file). “Unofficial” place names are changed to the accepted name. States and territories are represented as a two-character alpha. ZIP Codes must be verified or corrected, and a ZIP+4 add-on is appended whenever possible. (Note: ZIP Code and ZIP+4 are registered trade marks of the United States Postal Service.)

The standardized version of your input address will be returned the ZIP+4 appendage. The Primary and Secondary address data can be presented in several “views”.  The address elements can all be edited together or parsed and kept separate in seven distinct fields.

The “moved from” records on NCOA include either a personal name (consumer moves) or a firm name (business moves) – but never both on the same record. Business records don’t include any employee names.

Matching to the National Change of Address File

Each of your records will produce one of four possible results from NCOA processing:

New address.When your record matches to a record on the NCOA file, we provide you with the new forwarding address, whenever one is available. Roughly 84% of all NCOA records contain a forwarding address.

Addressee has moved, but a new address isn’t available. Roughly 16% of NCOA’s records do not contain a forwarding address. When your record matches one of these records, the record will be flagged. These are undeliverable addresses which should either be dropped from mailings, or used with “Or Current Resident” addressing.

Forwarding addresses are not available if (1) the person moved without leaving a forwarding address; (2) the old address is a PO Box, which the box-holder closed or didn’t renew; or (3) the forwarding address is outside the US (there are no foreign addresses on NCOA)

Possibly a move/possibly undeliverable.  This is an optional service which, when requested, can be performed at the same time as NCOA. If the name and address on your file is very similar to an NCOA move record, but does not meet the criteria for a match, we’ll code it as a possible move (called an “NCOA Nixie” or “Possible Nixie”). We can’t provide a new address — so you won’t be able to update the record — but you can take action on this information.

Many of these “almost matches” have moved, and will be undeliverable as Standard (A) mail. This option gives you warning that these records may be undeliverable. If these are prospect names, you’ll most likely drop them from mailings.

Didn’t match any NCOA record. There’s no move information to give you, but there is information about your input address. The first step of NCOA processing standardizes your input address, then verifies or corrects the ZIP+4 code and the carrier route code. This information can help improve your file’s address accuracy.

What NCOA processing won’t do

It won’t find everyone on your file who has moved. Some of the movers on your file will go undetected in the matching process. The matching logic (see above) requires an almost perfect match to the NCOA name and address. Some movers on your file will fail to meet the matching criteria, and won’t receive a new address. In addition, NCOA won’t provide addresses for temporary moves, moves that are more than 48 months old, or moves that are less than 4-6 weeks old  (these moves will not be on the NCOA database at the time of processing).

We suggest that you supplement NCOA by using one of the USPS’s address correction services, (such as “Address Service Requested” ) on your house files to pick up whatever NCOA is unable to correct.

(You can also use the DMCOA (Donnelley Marketing Change of Address) service.  It is our own service.)

It won’t keep track of executives who change jobs. The business moves on NCOA are just that –they are firms that have moved from one location to another. There are no employee names associated with these records. NCOA does not keep track of employees who move from one firm or location to another.

Limitations on the use of NCOA

NCOA processing has only one purpose. The Postal Service created NCOA as an aid to keeping mailing lists current. It can only be used to update mailing lists. It can’t be used to identify movers for any promotional purpose.

The Postal Service is prohibited by law from assisting in creating or supplementing a mailing list. The Postal Service, therefore, cannot allow mailers to use NCOA’s addresses to segregate or create a file of movers or to create a mailing selection of movers.

The new address cannot be flagged or segregated for the purpose of creating a “new movers” list, and it can’t be flagged as a special selection from a file. It can’t become a “hot line” name for mailings or list rentals.  It can’t be identified for any promotional purpose.

There is one exception to the rule. Mailers can use NCOA to maintain a relationship with their own existing customers. If NCOA indicates that a customer has moved, a separate mailing may be made to confirm the address change and to retain the business link with the customer.

NCOA can be used to improve the deliverability of mailing lists. The new addresses can be included in any mailing or mailing list selection as long as they are not identified as a move or selected because they are changes.

The use of NCOA is defined by the license agreement between the U.S. Postal Service and all NCOA vendors. The restriction applies to all users of the NCOA service.

Users of NCOA must sign a Processing Acknowledgment Form, as required by the USPS, to acknowledge compliance with the above restrictions, and to acknowledge receipt of  basic information about NCOA, which is presented in this User’s Guide.

LACS Processing

All users of NCOA service will be asked to sign the  NCOA Processing Acknowledgment Form annually, as required by the U.S. Postal Service.

All of our NCOA processing includes LACS processing at no additional charge.

LACS is a file of addresses that have been converted for 911 purposes. For each address that has been converted, the file contains the old version of the address (usually a rural route address), along with the new version (a street-and number address).

In some cases, the old address is a street-and-number address that has been revised. Why would a street address be changed? In some communities, the addresses along  a roadway are a mixture of street-and-number and rural route addressing. It’s often necessary to scrap the existing numbers and renumber an entire street to avoid duplication and to make the numbering sequential. It also may be necessary to change or add a street suffix (Street, Avenue, Lane, etc.) to avoid duplications of existing street names.

When an area undergoes 911 conversion, the post office will deliver to either the old or new address for a period of one year from the date that the address change appears on a postal file. After the year is up, the old form of address may not be deliverable. LACS processing is the only practical way for mailers to stay current with these address conversions.

In January 2000 the file contained over 5 million changes. Roughly 90% of these changes are conversions of rural route addresses to city-style addressing. The remainder are modifications of an existing street-and-number address. The file is updated monthly.

What LACS Processing Does:

The first step in LACS processing standardizes and ZIP+4 codes addresses on the input file. The standardized addresses are then passed against the LACS file.

In most cases, the process looks only at the address to determine matching. In a small percentage of cases the individual name is also required to determine a match. (The reason: if a  rural route box is shared by more than one household, or if the rural route boxes aren’t numbered to identify individual locations, a name is needed to determine the correct new address.)

If the input address is an exact match to an old address on LACS, we return the new version of that address. The output file will include the standardized version of the input address, plus information on the matching process, and a new address if a match was made.

The client input record (exactly as it was given to us) is appended to the LACS result. We do not change, update, or modify the client record unless we are specifically instructed to do so.

Output From NCOA with LACS Processing


When LACS is run in conjunction with NCOA, LACS processing is done twice. The first process compares the input addresses with the LACS file. The second process compares the NCOA move addresses with the LACS file.

When an input record matches a record on the LACS file (during the first process), we use both the input address and the new LACS address to search for a move on the NCOA file. This gives us a more thorough search against the NCOA file.

During the second process, we take all of your new “move to” addresses from NCOA, and pass them against the LACS file to ensure that you receive the most accurate version of  the new forwarding address.

The output from LACS and NCOA processing are combined into a 431-byte record that is appended to your original (unchanged) input record. The first 325 bytes contain our standard NCOA output format. Please refer to Database America’s  “Improving Deliverability with NCOA”, dated October 1999, for a detailed description of this data.

Whenever a match is found on the LACS file, we append a new (converted) address in positions 326-409 of the output record.  A code in position 421 tells you which record made a match to the LACS file — your input record (code I) or NCOA’s forwarding address (code N). If both the input address and the NCOA forwarding address made a match to LACS, only the NCOA version is returned.


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