How an expiring goal and increasing urgency affect donor conversion Experiment ID: #10131


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

Ended On: 12/27/2018

CaringBridge tried a new fundraising technique during the year-end campaign called the “Power Hour”, where they would raise money in small hourly campaigns that expired in 60 minutes. As they were running this campaign (via a sticky bar on their site), they wanted to monitor what happened to clickthrough rate and conversion rate as the number of gifts dropped. They analyzed the data with four gifts remaining and the data with two gifts remaining to try to understand how an expiring goal affects donor conversion.

Research Question

How does an expiring goal and increasing urgency affect donor conversion?


C: Four gifts to go
T1: Two gifts to go


Treatment Name Conv. Rate Relative Difference Confidence
C: Four gifts to go 14.0%
T1: Two gifts to go 22.0% 56.9% 96.4%

This experiment has a required sample size of 170 in order to be valid. Since the experiment had a total sample size of 453, 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
× 56.9% increase in conversion rate
× 0% increase in average gift

Key Learnings

Interestingly, there was no statistical lift in clickthrough rate—both “4 gifts left” and “2 gifts left” had a similar clickthrough rate, with only a 12% difference and 40% level of confidence. However, there was a statistically valid 56.9% increase in conversion rate once there were only two gifts left—which showed that the declining goal increased motivation and incentive. While this data is not necessarily actionable as progress towards a goal cannot be controlled, it can help direct timed communication efforts in relation to progress towards a goal. When should you send a “final appeal for help?” This experiment indicates that it may be more beneficial the fewer gifts there are left towards the goal.

Experiment Documented by...

Jeff Giddens

Jeff is the President 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.