How social proof improved the statement of belief’s email registration rate Experiment ID: #12988

Alliance Defending Freedom

Alliance Defending Freedom is an alliance-building legal organization that advocates for the right of people to freely live out their faith.

Experiment Summary

Timeframe: 3/11/2019 - 3/29/2019

After launching the statement of belief on the blog, ADF wanted to experiment with leveraging social proof as a way to improve pledge signature (or email capture / email registration) rates. The goal was to see if people would be more willing to add their name if they knew that they were joining with more than 10K other individuals.

Research Question

Will using social proof increase email acquisition rate of the statement of belief?


C: Join With Us
T1: Join with XX,XXX others


Treatment Name Conv. Rate Relative Difference Confidence Average Gift
C: Join With Us 4.5% $0.00
T1: Join with XX,XXX others 5.0% 9.6% 97.3% $0.00

This experiment has a required sample size of 18,467 in order to be valid. Since the experiment had a total sample size of 47,250, 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
× 9.6% increase in conversion rate
× 0% increase in average gift

Key Learnings

With a 97.3% level of confidence, we were able to validate an increase in email registration rate by 9.6%.

It appears that the social proof element increased pledge signature (email registration) rates when showing how many people had already signed the pledge. This aligns with the social influence theories that when it comes to the psychological or social phenomenon wherein people tend to copy the actions of others in an attempt to undertake behavior in a given situation.

In this situation, when they saw that nearly 20,000 people had already signed the pledge, they felt a level of confidence to go ahead and take that action, as well.

Our recommendation is to continue to test the social proof theory across other areas of the fundraising funnel (on other email capture pages, as well as donation pages) where possible to further validate the theory, or to determine if this is a lift only attainable/isolated to the pledge itself.

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.