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How to prune your e-mail list and reduce abuse complaints in MailChimp


Many companies are focused on growing their e-mail list, and rightfully so. But if you could improve the return on investment of your e-mail marketing program by pruning your list, would you?

First, I’d like to clarify that I’m not referring to “cleansing” bounces or unsubscribes from your list. Your e-mail vendor/software should do that for you. I’m saying that a large percentage of subscribers in your list don’t open or click any of your e-mail campaigns. So is it worth keeping them in your list?

Many companies don’t effectively track statistics of their e-mail lists, so you may be surprised to find out how few members of your e-mail list actually take action on messages you send to them. According to MailChimp, e-mail open rates average at about 25%. But that data is only based on a single campaign. How do you know what percent of your list takes action over time?

I’ve been a MailChimp customer now for a number of months and am increasingly impressed with the analytical information they provide on e-mail lists and campaigns.

MailChimp uses “Member Ratings” to rate each subscriber in your mailing list. The 5-star rating system uses a rating for “member” (subscriber) activity and is a quick visual measure of how engaged your subscribers are.

  • 1 Star- negative rating, this person has unsubscribe and re-subscribed, or soft bounced in the past
  • 2 Star- no activity, never opened or clicked, most likely a new member
  • 3 Star- this recipient has started opening or clicking your campaigns, limited activity
  • 4 Star- this recipient has started opening or clicking your campaigns, a little more activity
  • 5 Star- this recipient has started opening or clicking your campaigns, lots of activity

Why would you want to remove subscribers from your list?

If you’re working with a vendor to send email, you must limit abuse complaints to an extremely low number. A client of mine was sending e-mail to a list they had been building since the late ’90s, and when we brought the campaigns to MailChimp there were a relatively high number of spam abuse complaints when we sent the mailings. We needed to reduce the abuse complaints or risk MailChimp pulling the plug on our e-mail program.

Pruning also lowers the cost of mailing. If you aren’t sending to those that don’t open or click, your list size is smaller and you pay for a smaller subscription plan (or a per e-mail fee, whichever plan you have). In turn, you’ll generate a better return on your investment.

The pruning process

Here’s how we went about pruning our list, how we completely eliminated abuse complaints and improved the performance of our client’s e-mail campaigns.

Create a “best customer” segment
Because your marketing department might be uneasy (to say the least) about deleting names from your list, start by creating an audience segment in MailChimp. When you’re ready to send your next campaign, add all subscribers with a 3-star and above rating to a new audience segment. By doing this, you’ll be sending the campaign to only customers that have opened or clicked prior campaigns.

You’ll be amazed — and perhaps alarmed — that you’ll reduce your list size dramatically by doing this. In some cases, your new audience segment might be 20-40% the size of your complete list. Send a few campaigns to this audience segment and measure the results. For comparison purposes, you may also want to create an audience segment of only 2-star subscribers so you can compare results.

Caveat: The 2-star subscriber
The 2-star subscriber must be treated with care. While some subscribers with a 2-star rating might have never opened an e-mail from you in years, there also may be 2-star subscribers in your list that are brand new subscribers who have only received one or two mailings.

To solve this issue, create a new list and route all new subscribers to that list. Alternatively, MailChimp will also let you create an audience segment of 2-star subscribers that have recently joined your list.

Prune the list with confidence
Download a backup copy of your complete list, then delete all subscribers with 1-star and 2-star ratings. Note that if you don’t have a seperate list set up for new subscribers, be careful to only delete subscribers that have a long history of not opening your e-mails. This will reduce your list size dramatically and ultimately decrease the cost of sending campaigns.

Prune periodically
Note that you’ll need to repeat this process of segmentation and pruning periodically since some subscribers may naturally become disinterested or fall out of the purchase cycle for your product or service. I always recommend downloading a backup copy so you never actually delete subscribers that you prune from the list — rather, they are stored in your list backup file.

Real-world results

Our client, mentioned above, has been sending out e-mail marketing campaigns since 1998 and has been slowly building the list over time. We decided to prune their list using the above technique and saw the following results.

  • Their initial list size was cut by 69%, saving them $75 per month in fees.
  • Open rate was well over twice the industry average and their list average.
  • Click rate is 45% higher than the industry average and their list average.
  • Bounces are almost non-existent.
  • There have been no abuse complaints.
  • There have been only a handful of unsubscribes, and only one 4-star or 5-star subscriber has unsubscribed.

Our next step is to segment the most recent 2-star subscribers and send them a special discount to encourage them to visit our client’s site and purchase.

Posted 2009-11-25 11:38:43

About the Author

Rick Whittington Rick Whittington is the founder and Principal at Whittington Consulting. He has over 15 years of experience in websites and online marketing. Rick shows clients how to turn their marketing challenges into opportunities that yield measurable results. Connect with him on LinkedIn here.
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  • Thank you for these tips. We are carrying a number of inactive names/people on our database and I’ve been thinking about pruning those who have never opened an email. Thanks for the encouragement and suggestions.

  • Thomas Budinsky

    I love this approach, however, it is very difficult to persuade a client to try this method. Any suggestions…

  • Thomas,

    You’re certainly correct that it can be difficult to persuade clients to try this. Here’s what I would recommend. Get your client’s approval to send the message to the entire list, but segment the list into 1) one- and two-star rated recipients and 2) three-star and above recipients. Send them the same message, then show your clients the stats/results afterward. It may take a few mailings to convince them to prune, but you may eventually may get approval. At the very least, you’ll interest the client in campaign results and engage them in the process.

    I hope this works for you! Feel free to come back and share your results.

  • ziggy

    >>saving them $75 per month in fees

    But how much did you lose in sales? One sale could beat that.

  • Ziggy,

    There was actually an increase in sales that resulted from the e-mail campaigns over time. This could be due to seasonality, though none of the tests were not conducted after early November. Proof that if they don’t open or click, they don’t buy. Remember, we’re pruning the recipients that never open or click e-mails…

  • A problem i am seeing with that approach is that 2 star members are also members that have pictures set inactive in their mails so you would think they never opened your mails but in fact they might belong to one of your most reading newsletter customers, which have never clicked but enjoyed reading the stuff you sent them.

    An Alternative approch would therefore rather be sending your inactive users a mail to ask them if they would still like to receive your mails. if so they should click on a posted link. if they dont do this after you tried it 3 times every few weeks, throw them out of you list, they seem to be really dead or uninterested emaildresses.

  • Peter is exactly right. My Gmail accounts do not display images by default so its difficult to get the right stats. Further, i have had unsubscribes from email addresses who have, according to the reports, never opened an email. How they manage that? 🙂

    Don’t get me wrong, the idea is sound, just don’t take the ‘open’ stats as gospel..

  • Peter and Andre,

    At first glance, I’d say that you’re right that it might be of concern that some web-based e-mail clients don’t show images by default. I haven’t checked with MailChimp specifically to see if Gmail triggers an “open” even if images are not loaded by default.

    That said, the purpose of all of my testing was to reduce spam complaints, and I can share that since I started testing — and since I’ve written this article — the 1 and 2-star customer lists have always gotten a high occurrence of spam complaints, while the 3-5-star “best customer” list gets next to none. In that regard, this method is successful.

    The key here is paring the 1 and 2-star contacts, then segmenting contacts into 2 lists on subsequent sends (1 and 2-star customers and “best customers”). I don’t pare after every send, only about once every six months.

    I’m also measuring engagement in clicks, not opens, so though the “best customer” list open rate remains very high, clicks are much higher than the other list as well.

  • What I’d like to do is email my segment of 1 and 2 stars (removing those who have recently subscribed) and ask them to unsubscribe if they no longer want to receive emails.

    Would there be a problem with this approach? I.e. if I got a lot of unsubscribes would Mailchimp think I was sending out spammy emails?

  • Saba Amrin

    Good, it’s very nice & helpful article.keep it up.

  • I am glad Mailchimp uses member ratings, it’s a good way to simplify email marketing. Looks like our email list is in need of some pruning.

  • Julian Kingman

    Hi Rick, I’m in a situation where I revived some pretty old lists for a client, and got a high abuse rate and a warning from the ESP. Do you have any suggestions on how to proceed? I have about 80% of the 17,000-contact list that hasn’t even opened the first email, so naturally I want to see if I can convert a few more into readers, but I’m concerned that my complain rate may be too high and deliverability (and our account) may suffer because of it.

  • Rick Whittington


    In my opinion, there are a few responsible things to do:

    1. Reach out to your ESP and let them know the situation. Be up-front that you are trying to send only to people that want to receive communications.

    2. With your ESP’s permission, send an email just to those people that opened the first email. I would consider the others as non-subscribers at this point. The message in this email should state that you’re looking for their permission to keep sending email, and state some value props for staying on the list. Encourage those that don’t want mail anymore to unsubscribe.

    3. Get to work building that list back up.

    4. Have a plan to winnow your list on a regular basis. I can tell you that we look at our own list monthly. We pare from our list those that have incomplete profiles, those in countries that we can’t service, and sometimes other agencies. My philosophy? I want to send email to ONLY a) those that qualify to do business with us and b) those that want the communication.

    I hope that helps, and happy marketing!

  • Rick Whittington

    Thanks for the comment. How often do you prune your list? We make that a regular practice. So many companies think that the more subscribers they have, the better. Actually, the more qualified and engaged subscribers you have, the better.

    Best of luck!

  • Julian Kingman

    Thanks Jack,

    We’ve got it sorted out. I’ve followed steps 1 and 2. After running my second campaign, I had a 63% open rate, so I can see why it’s nice to prune a list! I have a plan to gradually re-introduce the other subscribers over the course of months to a year. Eventually, they’ll all be added, and then I’ll begin to prune it based on who has been receiving emails but not opening them.

    In hindsight, since there were multiple lists imported from multiple places, it would have been much better to send targeted emails from each of the list owner accounts promoting the new list, that way they would all be fresh and voluntary subscribers (even though they technically did subscribe).

    Thanks for your advice,

  • Rick Whittington

    Glad it worked, Julian!

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