How increasing urgency affects donor conversion rate

Experiment ID: #6583


CaringBridge offers free personal, protected websites for people to easily share updates and receive support and encouragement from their community during a health journey. Every 7 minutes, a CaringBridge website is created for someone experiencing a health event.

Experiment Summary

Timeframe: 05/04/2017 - 05/08/2017

CaringBridge was running a matching gift campaign to try to meet a match from a generous donor. As they reached the end of the campaign, they wanted to increase the perceived urgency to the reader of their final email. They had seen research that visually increasing urgency by putting a countdown clock in the email would improve response, so they created a treatment that did that. But they also wanted to test another concept that put the donor in the position to be the hero and finish out the campaign. Rather than messaging that they were “just short of their goal”, they quantified that they were “just a few gifts short”, which increased the perception that the donor could actually meet the goal.

Additionally, they tried to clarify language that had tripped up donors before. With a matching gift, they had traditionally used language like “double your gift”. But they hypothesized that this language could actually imply that they wanted to the donor to give twice as much. So, they tested simpler language that said “If you’d like to give (and have our anonymous donor match it),  you can use the link below.” They clarified the language on the link itself, from “Double my gift now” to “Yes, match my gift”.

They split the email file and sent a treatment to each half to determine a winner.

Research Question

Will increasing urgency and clarifying language increase conversion?


C: Control
T1: Added Urgency


 Treatment NameConv. RateRelative DifferenceConfidence
C: Control 0.07%
T1: Added Urgency 0.11%64.6% 99.9%

This experiment has a required sample size of 35,425 in order to be valid. Since the experiment had a total sample size of 212,249, 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
× 64.6% increase in conversion rate
× 0% increase in average gift

Key Learnings

The treatment, with the increased urgency and clarified language, produced a 64.6% increase in donations, along with a directional 24% increase in average gift. Because there were multiple variables in the treatments, further testing must be done to isolate each variable and quantify the lift from each individual variable.


Experiment Documented by Jeff Giddens
Jeff Giddens is President of NextAfter.

Question about experiment #6583

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