Merge-purge: Six steps to save money on wasted postage

Merge-purge and save money

If you work in direct mail, you have probably heard of the term “merge-purge.” And no, it is not what happens when you get sick to your stomach while accelerating to highway speed.

What is merge-purge?

Merge-purge (or dedupe) is a six-step process used to clean-up your direct mail list by identifying and removing unwanted or duplicate records to produce one unique and complete record for each consumer on your list. Not only will this eliminate the chances of you sending an acquisition mailer to an existing customer or mailing multiple pieces to the same record, but it will also assist in deliverability. Additionally, the merge-purge process can be used to identify individuals who appear on multiple lists, called ‘multi-buyers’ or ‘multis’, as these consumers may be considered more responsive.

Merge-purge is generally performed by the mailer’s direct marketing agency when onboarding or combining lists. Marketers may also adopt this process during regular CRM and house files data hygiene. Merge-purge can be conducted on direct mail, email and digital marketing lists.

Six steps to save you money

1) Pre-merge-purge count approval

This may feel like a no brainer, yet this is a crucial first step to preserving your timeline. Verify you have received all your ordered lists and that record quantities and list priorities are accurate.

2) List conversion

No two data files are delivered in the same file type and format, often varying in length and layout. Once you have confirmed receipt of all the records from your various list sources, all input data must be converted to a consistent format to successfully start the merge-purge process.

3) Address hygiene and standardization

To ensure the USPS can successfully deliver your mail piece, all names, addresses and abbreviations should be uniform. Carrier routes, delivery points and zip4 fields must also be complete and correct. Depending on your list source and type, standardization may automatically be updated via the United States Postal Service’s National Change of Address database (or a proprietary database) but should still be verified during this step.

4) Merge-purge matching logic

Advanced data-matching logic is used to identify duplicate records or combine data from multiple lists to build one complete record. There is flexibility in how you can apply or layer matching logic throughout your data inputs based on your business rules. Four prevalent matching logic approaches are:

  • Address only: Name fields are ignored; entries are matched based strictly on address.
  • Household: First names are ignored; entries are matched based on last name and address.
  • Match-code: Combination of certain characters of last name, address and zip5.
  • First name, last name and address: Nothing is ignored; all inputs must match.

5) Your sample list

To make sure your final mailing list is representative of your audience, you should select a sample across all lists to make up your total volume. This step is especially important if you are conducting any type of package testing. Typical sampling methods include:

  • A/B split: A simple split of lists.
  • Random: Randomized selection across all lists or a group of lists.
  • “Nthing”: Includes the same percentage from each zip code in all lists – creating an almost perfect sample because it verifies your distribution is the same across your audience.

6) Final count approval

At the end of this process, you should have a final mailing list, a dropped record file and if applicable, a holdout file. As a last quality control check, confirm your mailing list quantity accurately represents your expected mailing volume.


Conducting this six-step merge-purge process is an extensive practice with many complex factors. It takes a human touch to balance the automated and manual aspects of each step and catch the minor errors that may be missed by software. Partnering with a best-in-class agency will ensure your direct mail package will efficiently land in the hands of your optimal audience.

Looking for more ways to protect your direct marketing investment? We have ideas to offset postage hikes, optimize your digital marketing budget, find the right agency for your goals, and more on our blog.


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