Want to keep up on postal happenings?

Interpreting Return Codes

Beyond the return code there is a wealth of information that CASS returns which can inform you about the mailability of the piece, and often how the information on it could be corrected.

First, there are several return codes that mailers often are unfamiliar with. The most misunderstood is Return Code 39. This is a LACSLink conversion which can drastically change the delivery address on a piece. These conversions were originally created by emergency first-responders wanting to make rural addresses easier to locate when calls came in. The Post Office borrows this database to improve deliverability. So while the addressee or the mailer may takes issue with this conversion, these changes almost always lead to more reliable deliveries.

Most mailers know the basics of the return code field – namely that Return Codes 31 and 32 are generally deliverable.

  • Return Codes 21, 22, and 23 may not be deliverable, for a variety of reasons. A match, or close match could not be found; there were multiple responses; or an error in the Primary.
  • Return Codes 33, 10, 11, 12, 13 and 17 are usually undeliverable, but the return code should give you an indication of what needs correcting.

We find that most mailers stop here and do not pay attention to the plethora of additional information CASS provides across several other fields. ZIP+4 and DPV Footnote codes tell you either which part of the address was used to make a match or which part is incorrect. There are 44 possible ZIP+4 Return Codes that can occur in almost any combination, helping to further narrow down the problem area of a bad or questionable record. Additionally, there are 14 DPV Return Codes which confirm what part of the provided address information was used to supply the DPV results.

The DPV Confirmation, DPV No Stat and DPV Vacant codes, along with the actual Delivery Point information, is a frequently overlooked set of return information. DPV Vacant is simply a Y/N field, telling you if the address is flagged as vacant despite being a valid USPS address. DPV No Stat identifies an established delivery address, versus addresses that are recently vacant or new construction. DPV Confirmation, along with the presence of a Delivery Point, often makes or breaks an address. The Delivery Point is the last two digits of the Primary Number, but it is only assigned if an address is confirmed as deliverable. Any such address will have a DPV Confirmation = Y. The opposite of this is a DPV = N, which represents a record marked as undeliverable. The main point of contention is that a record with a Return Code = 31 can receive a DPV = N, resulting in no Delivery Point and no ZIP + 4.

These records are explicitly undeliverable, despite the seemingly valid return code. The most common explanation is that the Primary number is within an acceptable range for that street within the ZIP Code provided, but the actual primary number does not exist.  For example, ZIP Code 12345 has a primary range of 1-99 on Main Street. This means 75 Main Street falls within the range, and will get a return code = 31. After this is established, DPV checks the actual deliverable addresses listed in their records for 75 Main Street. If no such record exists, this address receives a DPV = N, as it is not deliverable despite being within the expected range of street addresses. There are two other possible values for this field, an S and a D. Generally speaking, they mean that the address secondary or box number has not been confirmed as deliverable, but the address has not been explicitly deemed undeliverable either. These are similar to the 21-23 Return Code range, in that they may be correct enough to be delivered, but often are not eligible for a 31 due to an error in the provided information.

The last bit of return information we find underused is the LACSLink return code. The most basic return is A, which mirrors Return Code 39, and simply tells you a match was made to the LACSLink system and return information was provided. Other LACSLink Return Codes are defined below.

Armed with all of this information we can make better decisions about what can be delivered and how to correct pieces that are lacking. Leveraging this information to leave out bad addresses that look good, and correct mediocre addresses will go a long way to improving your relationship with the post office as well as your return for each mailing.

As always please contact BCC Software Customer Support at 800.624.5234 if you have any questions regarding this trove of information that is hidden in plain sight in your CASS returns.

Looking for NCOA Return Codes?

Download our NCOA Return Code Reference Guide – or sometimes simply referred to as an NCOA form – here.