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Case Study: Resend Emails to Increase Open Rate from 20% to 29%

I want to share with you my own case study on how I increased the email open rate from 20% to 29% by changing the subject line and resending emails to those who hadn’t opened the previous one.

I have talked about behavioral segmentation lots of times on the Mailigen blog. The same with my favorite tip: select those who haven’t opened your email and send it to them again with an altered subject line. I believe this pays off and it can be better demonstrated through a real case study.

Starting with a 20.5% open rate

The story is about the Mailigen monthly newsletter. The last one I sent was about symbols in subject lines. So I decided to show an example and include one in the newsletter subject line. The results for the subject line Make your emails standout with symbols ツ were quite good showing a 20.5% email open rate which is average in the industry. Here is how the newsletter looked.

Mailigen newsletter

After resending emails –  8.6% open rate

But still I wanted better results, so I used our latest feature of behavioral segmentation. A week later, I selected all those who hadn’t opened the newsletter, changed the subject line to Send emails with awesome ღ symbols in the subject and resent the same newsletter. The second newsletter was opened by 8.6% of those who hadn’t opened the previous one.

resending emails

Ending up with a 29% open rate

Calculating together both newsletters with a 20.5% and 8.6% email open rate, my email performance resulted overall in a 29.1% open rate exceeding average industry results. Not bad at all!

Email open rate

Hope you find this useful and will get value out of my case study for your own email campaigns. Mailigen’s new feature allows you to split your database into segments by recipients’ activities within a specific email marketing campaign, including links they have clicked.

There are also some great case studies of our awesome customers to learn from. Let me share two of them.

#1 Change the idea of the subject line

One of our customers sent an email campaign with a subject line inviting their customers to call and order a meal. Their email open rate reached 18.1%. A week later, they selected those subscribers who hadn’t opened the previous email and resent it to this segment. They not only changed the subject line but also the concept of the subject line by including a phone number in it. The second email was opened by another 7.7% of subscribers, resulting in better overall engagement.

#2 Send SMS to those who haven’t opened the email

Another idea on what to do with those who haven’t opened your email campaign is to send a text message, as did our customer from the pharmacy industry. After having sent an email campaign and scoring a 23.7% open rate, they sent an SMS to the rest of their subscribers thereby considerably increasing customer awareness.


Whether you are resending emails with a changed subject line or send a text message to the inactive subscribers, it will increase engagement and thus improve overall business results. Try it out yourself and let me know!

If you want to learn how to send better emails to your subscribers, follow my blog posts every week. And if you have your own case study that you want to share with our readers, feel free to get in touch with us. 

Case Study: Resend Emails to Increase Open Rate from 20% to 29%
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