How sending a personal follow-up affects open rate

Experiment ID: #11730


Experiment Summary

Timeframe: 07/20/2016 - 07/21/2016

We wanted to re-send a live broadcast invitation to email recipients who got the original invitation, but never opened it. This is a fairly common practice – filter for non-opens and schedule your email for a different time, often with a different subject line that hits on a different aspect of urgency or importance.

We wondered if instead of running the resend in the typical marketing fashion, we could lift open rates by writing a personal follow-up email that you might get it if you didn’t respond to an email from a colleague.

Research Question

Will increasing the personal tone of the subject line and preview text in a resend affect open rate?


C: Standard Resend
T1: Personal Follow-up


  Treatment Name Open Rate Relative Difference Confidence
C: Standard Resend 10.5%
T1: Personal Follow-up 22.0% 109.8% 100.0%

This experiment has a required sample size of 80 in order to be valid. Since the experiment had a total sample size of 3,377, and the level of confidence is above 95% the experiment results are valid.

Flux Metrics Affected

The Flux Metrics analyze the three primary metrics that affect revenue (traffic, conversion rate, and average gift). This experiment produced the following results:

    109.8% increase in traffic
× 0% increase in conversion rate
× 0% increase in average gift

Key Learnings

With an increase of 109.8% in open rate, we’ve learned that our email recipients are much more likely to engage with a re-send email that feels like a follow-up email a colleague or friend might send.

Experiment Documented by Dan VanMilligan
Dan VanMilligan is Implementation and Optimization Specialist at NextAfter.

Question about experiment #11730

If you have any questions about this experiment or would like additional details not discussed above, please feel free to contact them directly.