Which works better in subject line? Tying it to last week, or a fresh provocative subject line? Experiment ID: #14382

Care Net

Experiment Summary

Timeframe: 4/6/2019 - 4/17/2019

This is for our weekend update email. Last week I talked about Unplanned, this week I was talking about it again, but there was new material that was provocative. 

Research Question

Does harkening back to a previous email in the subject line do worse that introducing a new, more interesting subject line. 


C: More thoughts about the pro-life movie Unplanned
T1: Planned Parenthood revealed why they can't win


Treatment Name Open Rate Relative Difference Confidence
C: More thoughts about the pro-life movie Unplanned 34.6%
T1: Planned Parenthood revealed why they can't win 44.5% 28.5% 99.9%

This experiment has a required sample size of 189 in order to be valid. Since the experiment had a total sample size of 1,136, 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:

    28.5% increase in traffic
× 0% increase in conversion rate
× 0% increase in average gift

Key Learnings

We learned that (at least in this case) the new subject line did MUCH better. I do believe that this is in part due to saturation of the subject discussed in the original email (the movie Unplanned) but the jump in improvement was definitely telling. 

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Experiment Documented by...

Kevin Peters

Kevin is the Chief Technology Officer at NextAfter. If you have any questions about this experiment or would like additional details not discussed above, please feel free to contact them directly.