How an empty thermometer affects donor conversion Experiment ID: #5858

Hillsdale College

Founded in 1844, Hillsdale College is an independent liberal arts college with a student body of about 1,400. Hillsdale’s educational mission rests upon two principles: academic excellence and institutional independence. The College does not accept federal or state taxpayer subsidies for any of its operations.

Experiment Summary

Timeframe: 12/13/2016 - 12/15/2016

Hillsdale College started their calendar year-end campaign with the intent to launch a thermometer on their donation page once they achieved a critical mass of donations toward their goal. Previous testing had shown that the ideal time to introduce a thermometer to maximize conversion was when the goal was at least halfway met. However, the team wondered if putting the empty thermometer on the page would disincentivize visitors from giving.

They launched a treatment with the empty thermometer and closely monitored the results to determine a winner.

Research Question

How will an empty thermometer affect donor conversion?

MECLABS Conversion Factors Targeted

C = 4m + 3v + 2( i - f) - 2a ©

Copyright 2015, MECLABS


C: Control
T1: Empty Thermometer


Treatment Name Conv. Rate Relative Difference Confidence Average Gift
C: Control 43.6% $85.81
T1: Empty Thermometer 46.0% 5.5% 51.5% $76.66

This experiment has a required sample size of 3,349 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 page with the empty thermometer failed to reach statistical validity, which showed that it did not disincentivize donors from giving. However, Hillsdale chose to remove the empty thermometer from the page to maximize the “reveal” of the thermometer once significant progress had been made toward the goal. This result may have been clouded by the fact that these donors were the first to respond to the campaign, and tended to have the highest motivation.

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Experiment Documented by...

Jeff Giddens

Jeff is a Senior Vice 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.