What You Should Know About a Merge-Purge

Planning your circulation strategy is about more than just selecting which prospect names or housefile segments to mail. Merge/purge is critical to the success of your mailing, too.

How you instruct your service bureau to run the merge can affect your mailing results. This month, I’ll discuss how to assign list priorities, treat multi-buyers and deal with family groups.

Of course, the main reason for running a merge is to identify and eliminate duplicates from your mail file. A merge will identify two types of duplicates: duplicates between files (known as inter-file dupes) and duplicates within a file (or intra-file dupes).

When duplicates are on a file, the merge can assign the surviving record randomly across all lists or based on a defined priority by list. That is, the merge assigns which list retains the record that appears on more than one list.

Multi-buyers

The merge also creates a file of duplicated records for future mailings — these are called multi-buyers. They’re names that have “hit” on one or more rented lists.

Normally, they’re categorized by how many times the record appears in the merge (for instance, a two-time multi is a record that appeared in the merge twice). It was mailed for the first time under the list where it was assigned, and it can be mailed a second time in a future mailing for no additional list-rental expense (after all, you’ve already paid two list owners for the same name). Multis are captured only for outside lists since there’s no benefit to pulling housefile names out of their RFM (recency, frequency and monetary value) cells.

The surviving multi-buyer information also is retained in the merge. When the merge assigns duplicates based on random or prioritized allocation, the duplicate name that’s retained is tagged as a multi-buyer. Typically, the merge report identifies the following: “singles” that appear in the merge only once; “multis” that appear in the merge more than once (and were retained on that list); and “output,” which is the combination of the two.

Family Groups

Family groups are identified so that “same” lists don’t falsely create a multi-buyer. For example, if you take two selects from the same list owner, they should be unduplicated before they’re sent to your service bureau. If they aren’t, the duplicates between the files could be considered multi-buyers. In this example, they’re not multis but the same record being pulled twice.

By identifying these in the same family group, the merge would consider them to be intra-file duplicates, which can be deducted from your list-rental invoice.

Housefile Priority and Family Groups

How can you use this information to establish priorities and family groups? Following are four rules:

1. Always make your housefile (your customers) the top priority, along with the best-performing RFM groups. And put the lower-performing RFM cells at the bottom. If your file has been updated, there will be few duplicates. But it’s still important that duplicates be appropriately associated with the top-priority RFM cells.

2. Sometimes you’ll mail or re-mail only a portion of your housefile. If the duplicates within the housefile were random, you may drop a record that actually is from the higher RFM priority. By prioritizing your housefile, you’re more likely to mail the best performers.

3. Assign your housefile buyers to the same family groups. In this way, duplicates within the housefile will be considered intra-file dupes. By doing so, you’ll know which multis credited to the housefile also will have appeared on another list (other than the housefile).

4. If you aren’t mailing all of the housefile records you put in the merge, don’t drop what’s been identified as multis. These are primarily records that came from an outside list that hit to your housefile, and they may perform quite well.

Prioritize Specific Prospect Lists

Theories abound for setting outside-list priorities. By making one group of prospects (e.g., cooperative database names, your best-performing outside prospect lists) more important than another, that group will have the most multis assigned to it and therefore, a performance advantage. Following are some points to consider:

- Is there a true reading of their performance? Should you measure all outside lists on a level playing field?

- If you’re renting a lot of names and can work out net-name arrangements, there’s an advantage to showing a lower net on certain rental lists. By giving a higher priority to exchanged names or names garnered from a co-op database, you’ll net lower on the list that you pay for, and you’ll be able to use this to negotiate a better arrangement. Note: This can be hard to track when measuring performance over time.

- It’s harder to find outside lists that perform well if they don’t have multis allocated. So if you’re looking to grow your business, this approach may not work for you.

- If you net low out of the merge, check to see if the lists are duping against one another or against the housefile. If they duplicate to one another, there’s no reason to bring all of the names into the merge. If they dupe to the housefile, it’s best to mail net reuses or to negotiate a better net arrangement with the list owner.

Whether you decide to prioritize certain outside lists or keep them random, stick to the same routine for understanding a list’s performance in time. In other words, be consistent in your approach. Following are two guidelines for dealing with family groups when prospecting:

- Look at high intra-file duplicates as an indication of how well (or not well) the mailer maintains its file and how accurately the mailer processes list orders. If there’s a consistent problem, proceed with caution.

- Deduct any intra-file duplicates from your list-rental invoice.

Outside List-rental Restrictions

What if certain list owners won’t let you make promotional offers to their customers? How do you keep these people from being mailed? What happens if they show up on the multi-buyer file?

In the merge/purge, put all rented lists on “random allocation.” This means that if a name hits two lists, the name resides on list A and is dropped from list B. The next time a duplicate is found, it resides on list B and is dropped from list A (hence, they’re randomly allocated). It’s likely that a name on any given list will be knocked out, while the name survives on another rented list. Bottom line: As long as you don’t mail the offer to the rented list whose owner declined your offer, you should be fine.

To ensure your peace of mind, instruct your service bureau to put the lists that won’t allow promotions into the merge with the lowest priority. (This will yield the maximimum number of catalogs that can get the offer). Also have the service bureau de-dupe these lists against each other to knock out any multis. Then have the bureau retain the original keys with the multi-buyers and pull these keys for the lists, so you don’t mail these names a second or third time when mailing the multis.

Word of caution: By putting the list that disallows promotion in the lowest priority, your mailing will perform at a lower rate if no multis are attributed. Eventually, the list may be dropped out of the list pool that’s mailed because of poor performance. Unless you take this into consideration and factor this list’s performance back up to what it would have been, it’s a sure way to eliminate from future mailings a list that works.

Your merge should be used to maximize your mailing, not just to remove duplicate records. By considering how you’d like duplicates and priorities assigned prior to the merge, you’ll get the most out of your merge.

Next month: More circulation-planning strategies.

Stephen R. Lett is president of Lett Direct, a catalog consulting firm specializing in marketing, circulation planning, forecasting and analysis. He can be reached at (302) 541-0608 or by e-mail at slett@lettdirect.com.