How to drop the complaint rate by 80%?

In Email Marketing by Xu Cui2 Comments

When doing email marketing, we hate to see the recipients click “spam report”. My friend Xiaoshan has noticed that many users who clicked “spam report” are using Yahoo email. To that end, we did an analysis to see which email complains most.

Top spam report

Top spam report

As seen in the chart, Yahoo email subscribers contributed about 60% of the spam reports. But you may ask, maybe it’s because we have many Yahoo subscribers. To that end, we calculate the probability to click “spam” for each domain (number of spam complaints / total number of subscribers).

Probability to click “spam report”
aol 6% 3%
yahoo 2%
comcast 2%
hotmail 1% 1%
gmail 0.005%

As we can see, aol,, yahoo, comcast and hotmail users have a high probability to click “spam report”. Since email servers are very sensitive to spam complaints, it’s advisable to remove these emails from our campaigns if possible and your complaint rate will drop by 80%. We also calculated the probability for Gmail and it turns out it’s extremely low. So we don’t have to worry about gmail.

Lesson Learned:

  1. To reduce complaint rate, it’s better not to email aol, yahoo,, comcast, hotmail and users if possible. It will drop the complaint rate by more than 80%.
About the Author

Xu Cui

Xu is the founder of BizGenius and research scientist at Stanford University. He loves data analysis.

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  1. This is absolutely true.

    I have an email list that contains mostly AOL users – and they complain constantly.

    As a way to test why this was happening, I created an email account with AOL.

    Here’s what I discovered…

    The reason people mark emails as spam so much with AOL is because AOL makes it so easy. There’s literally a way to mark multiple emails as spam with just one click of a button.

    And if somebody’s lazy, they just mark all emails as spam to save time.

    With ISPs like Google, this is not the case. It’s actually much more difficult.

  2. Author

    Thank you for sharing, Seth. Sometimes a user “complained” because they click the spam button by accident.

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