How adding a third party testimonial to a landing page affects conversion rate Experiment ID: #8106

Heartlight Ministries

Heartlight provides a safe haven of hope for 56 struggling teens at our residential counseling center located in Longview, Texas. Our atmosphere of relationships creates an arena of change for teens and parents lost in a broken world. And second, Heartlight offers help and direction for parents of all teens through our Parenting Today’s Teens radio program, our books, parenting resources, and seminars and conferences….all dedicated to offering effective and practical ways for parents to counter the influence today’s culture is having on their child.

Experiment Summary

Timeframe: 11/8/2017 - 12/18/2017

Heartlight Ministries launched an offer called When Your Teen is Struggling, and wanted to test whether including a testimonial from a well-known Christian author, Joe White, would increase conversion on the landing page. The rest of the copy and elements of the page remained the same.  

Research Question

Does adding a testimonial from a well-known figure to a landing page increase conversion rate?


C: No testimonial
T1: With Joe White Testimonial


Treatment Name Conv. Rate Relative Difference Confidence
C: No testimonial 47.2%
T1: With Joe White Testimonial 45.4% -3.8% 60.3%

This experiment has a required sample size of 5,889 in order to be valid. Unfortunately, the required sample size was not met and a level of confidence above 95% was not met so the experiment results are not valid.

Key Learnings

The decrease of 4% on the treatment page was not statistically valid, but it’s possible that the placement of the testimonial distracted people’s eyes from the line of copy, or that the author of the quote was not influential enough to have a strong effect on conversion rate.

This concept would need to be tested again to be a statistically valid learning, and might be more impactful if multiple statements were used.

Experiment Documented by...

Allison Jones

Allison is an Optimization Associate 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.