Culling your email list

By Mark Brownlow

Several recent articles I've read suggest culling your address list of unresponsive addresses so as to boost your open rates and other metrics. There are many good reasons for culling your list, but the implication is that it improves your results, automatically and immediately.

But most -- sometimes all -- of that immediate improvement is meaningless. It's just massaging the numbers.

Removing the unresponsive addresses does not make the remaining people on your list suddenly more likely to open or act on an email. Nothing has changed for them. So the actual number of opens and clicks and conversions doesn't change. What changes is the total number of emails against which these totals are compared.

You get the same total number of people opening emails, but the percentage is higher because you're now sending out fewer emails.

Take this example...

List size: 500,000 addresses
Open rate: 40% of sent emails (200,000 emails opened)

Take out 100,000 addresses that have never opened or responded to an email and change nothing else about your email marketing:

List size: 400,000 addresses
Open rate: 50% (200,000 emails opened)

Well done, you increased your open rate by 10 percentage points. But exactly the same number of people opened the email as before. The increase is misleading.

No, I'm not suggesting culling your list of unresponsive addresses is a waste of time. On the contrary, here are some of the real reasons why you should...

• It reduces infrastructural costs, like those associated with sending out the emails (fewer to send means lower costs).
• You can focus more on the needs of the most valuable recipients, so your segmentation efforts, content development etc. should all become better targeted and more effective.
• Your analyses will improve, since meaningful changes in, for example, test results won't be obscured statistically by a large number of unresponsive recipients.
• The market value of your list may improve, if you assume that a small responsive list is worth more than a large unresponsive one.
• If you send emails to people who are not responding and thus not interested, the chances are that some of those will eventually report you as spam, even if it's just to divert you to the delete folder. So culling should also improve deliverability, helping, for example, to keep you off blacklists and on whitelists.
• If you have less overall mail to deliver, then a greater proportion of those emails will arrive at the time you intended - you don't have to spread them out to account for delivery capacity problems or to keep within delivery limits imposed by particular ISPs
• Higher open rates, even if meaningless, look better (which may be important for internal politics and external PR)

Culling unresponsive addresses will lead to meaningful and important improvements in your bottom line results and success metrics. But don't let the numbers mislead you.

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