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Why Low Bounce And Complaint Metrics With Email Delivery Are Not Enough

(This post was previously published by our partners at

Much like judging a book by its cover, you can’t judge an email campaign solely by metrics like bounces and complaints alone. As an Email Service Provider (ESP), we’ve seen a vast array of email campaigns where bounces and complaints were routinely low, but that over time, email consistently landed in the spam folder. Sender reputation is established and tracked for the sending domains and IP addresses. Bounce, complaint, open and click metrics are just one thing that mailbox providers are looking at when determining sender reputation.

Here are some of the other things that can impact your sending reputation:

Open & Click Metrics

One simple metric that can help you gain insight into how your sending reputation might be viewed is through open and click metrics. Mailchimp has posted some great research for industry averages, but overall, it’s not the final open rate that is the determining factor. Having low open or click rates is just a leading indicator that there may be another problem. Low engagement rates could be signs that you’re emailing users too frequently, not providing valuable enough content, or even larger problems like that your recipients are not expecting to receive mail from you.

Users Moving or Deleting Your Mail

Mailbox providers are able to track a lot more than you can from the sender perspective. If a significant amount of recipients set up filters to filter your mail out of their inbox, move it manually, or even delete it regularly, it may be directly reflected in your sending reputation. You can’t control this or even see when it’s happening, so what should you do? Since you know that users who delete or move your mail regularly won’t be opening or clicking this mail, you can solve the problem holistically through removing older recipients that don’t open or click your email. By doing it this way, you’ll be removing them from your lists before users even have to set up filters, or continuously move or delete your mail.

Overall Sender Email List

Spam Email
This type of SPAM is welcome. The other kind? Not so much.

It’s just plain illegal to send to people that have not opted in to receiving your mail. There’s lot of companies that take 3rd party opted in recipients and try to rent or sell those lists for use. While these companies may be able to get around the legal regulations, do not send to these email lists if you want you want to maintain your sending reputation!

These recipients are not expecting mail from you, and you will experience low engagement and high complaints. Additionally, most lists like this have spam traps mixed in with valid email addresses, which helps reputation monitoring companies track which senders are sending to these rented or purchased lists.

As the definition of ‘spam’ has continued to evolve from illegitimate scams (think ‘VI@GRA’) to more legitimate mail that may have lost recipient interest, you’ll need to continue to evolve on how you run your email program.

As you’ve learned above, no one metric alone is enough to focus on to ensure you are reaching the inbox, and some metrics like how users move or delete your mail will be completely unseen by senders. To keep reaching the inbox, you’ll need to ensure you understand your recipients behavior, give them preference centers to configure how they want to receive email, and continue to send quality content that they want to receive.

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Whois: Mike Veilleux

Mike Veilleux is a Director of Product Management at Oracle Dyn Global Business Unit, a pioneer in managed DNS and a leader in cloud-based infrastructure that connects users with digital content and experiences across a global internet.