How adding social proof impacts email sign ups Experiment ID: #17083


Experiment Summary

Ended On: 7/22/2019

When we redesigned the NextAfter blog, one of the goals was to increase subscribers/email signups through both the placement and message of the offer. One new sign up placement was a  a large call to action area above the blog and we wanted to see which message would encourage people to sign up. For the control, we kept our old/standard value proposition about what you will get if you sign up but for the treatment, we added in the number of people subscribed and who they were — fundraisers and nonprofit marketers — to add social proof and clarity.

Research Question

Will adding social proof – the number of other people who receive email updates – increase the likelihood of email signups?


C: Control
T1: Treatment #1


Treatment Name Conv. Rate Relative Difference Confidence
C: Control 1.1%
T1: Treatment #1 3.9% 246.7% 97.7%

This experiment has a required sample size of 186 in order to be valid. Since the experiment had a total sample size of 986, 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:

    0% increase in traffic
× 246.7% increase in conversion rate
× 0% increase in average gift

Key Learnings

By using social proof, number of others subscribing the blog, it helped increase conversion as it helps build credibility (if that many other people read it can’t be bad) and possibly even a bit of ‘loss aversion’ (I don’t want to miss out on what they are getting). The added clarity of saying who else is subscribing and who the blog is for — fundraisers and nonprofit marketers — also could’ve played a role.

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.