Crash Course Guide on Data Hygiene

Crash Course Guide on Data Hygiene

No matter what type of marketing you are in, no matter what industry you are in, the most valuable tool in your marketing tool box is your contact list.  A contact list or database contains a wealth of information on a population of people that you are marketing your product or service to.  The list may be made up of current or past customers, prospects who have opted-in to your marketing, prospects who have expressed interest in your product or services, prospects who have purchased similar products or services, or prospects who fit your customer demographic.

While this list is extremely valuable, you have to remember that the data in the list is always subject to change as your prospects’ lives change.  One of the best investments you can make to maximize the potential of your list is to perform regular data hygiene.  Data hygiene is the process of reviewing your data to ensure that it is as accurate as possible.   In direct mail, this can include seeing if your prospects have moved recently, so that your direct mail pieces are delivered properly and not returned as undeliverable.

Data hygiene allows you to:

  • Verify and correct addresses before you mail
  • Remove duplicate addresses from your lists
  • Qualify for USPS Bulk mailing discount
  • Minimize delivery delays by only using valid addresses
  • Eliminate mailings to undeliverable addresses

The USPS offers many tools and services that you can use to review, clean and update your mailing list.

National Change of Address Database

The National Change of Address, or NCOA, database was developed by the United States Postal Service (USPS) to allow businesses to update their records to include the most accurate address information for their list members.[1]  The NCOALink product is only available through a license via the USPS, so contact your direct mail vendor to see if they have a license.


Delivery Point Verification (DVP) and Coding Accuracy Support System (CASS) are two tools also developed by the USPS to improve the quality of address data.  DVP is a tool that compares the addresses in a list to the list of valid mailing addresses and provides replacement addresses for those that are invalid.  CASS is a certification tool that examines the accuracy of software that provides address correction.  Software products have to be certified by the USPS on an annual basis.

Deceased Processing

A different challenge posed to marketing professionals is the deaths of some people on their list.  While it financially does not make sense to send direct mail pieces to people who are deceased, it can also be highly uncomfortable to the surviving family members to receive direct mail in the deceased’s name.[2]  There are tools available to assist with reviewing your database to remove the names of the deceased, and depending on your demographic, could result in a significant return on investment (ROI).

Data Appends to Correct Data

While the address corrections described in the previous sections will help with your overall deliverability, you probably also segment your list to target specific demographics within your list, or you may want to contact your prospects through a different medium, such as email or social media.  Data append tools can help to verify and/or correct demographic data or contact information to ensure that the right message reaches the right prospects in the right way.


If your company has multiple mailing lists, it might be cost-effective for you to perform a merge/purge operation.  The “merge” portion of this action pulls all of your mailing list data into a single list, while the “purge” portion removes duplicate data, where the same individual may have resided in both lists.  This will reduce duplicate mailings and give you a single, cohesive list to work from. 

Merge/purge can be performed to different degrees, including individual, household, and address.  For example, a university may want to purge multiple listings for a single individual to eliminate duplicate mailings and reduce printing and postage costs.  However, if two alumni of the same university are married, then the university will want to limit some of their mailings to one per household for general mailings, but still retain the ability to target each of the alumni individually for mailings that are topically specific to each person.

Apartment Append

Sometimes, apartment or subunit numbers are not attached to address files, which can result in mailings being delivered to the wrong address or not delivered at all.  Apartment databases can be used to append this additional data to incomplete addresses to increase the deliverability of your mail pieces. This append is used mainly on residential data.

DMA Mail Preference Service

The Mail Preference Service (MPS) is a tool developed by the Direct Marketing Association (DMA) to allow mail customers to opt into a “do-not-mail” list.[3]  All DMA member companies are required to filter their mailing list against the MPS list.  However, customers who have opted-in to contact with a company may still receive mailings even if they have signed up for the MPS.

Prison Suppress

This action suppresses those prospects on your list that currently have an address associated with a state or federal prison.  These prospects can be later reverted to active status once they are relocated to a non-prison address.

Proprietary Change of Address

While the USPS does maintain the NCOA database, not everyone submits their change of address information to the USPS when they move.  Proprietary Change of Address (PCOA) tools take data from a variety of private sources to augment the data provided in the NCOA tool to provide a more complete and accurate address list.  Using a PCOA should be done in conjunction with NCOA because of its limited scope.[4]

Case Study

We (Ballantine) performed data hygiene for a California-based medical device company with a large contact database of 802,896 records. Because our client targeted senior citizens, we were particularly concerned with removing the records of those who were deceased and updating address information.  We first processed the database through the deceased suppression file, which yielded 35,630 names, or 4.44% of the total file.  Next, we processed the file through NCOA.  Of the 802,896 records, 118,570 records, or 14.77% matched.  108,976 left a forwarding address, allowing us to update the firm’s database with more accurate address information.  The remaining balance of 9,594 records left no forwarding address, making them undeliverable, so these records were suppressed.

Data hygiene allowed our client to significantly improve the deliverability of their message and to eliminate mailings to deceased contacts and undeliverable addresses, resulting in a significant cost savings for its subsequent mailings.