Hillsdale College

How an optional phone number field impacts donor conversion

Experiment ID: #6086

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: 01/17/2017 - 02/08/2017

Hillsdale College was looking for ways to continue to improve their donation page. One of the factors that potentially hindered donor conversion is the friction associated with filling out the donation form. In an effort to reduce that friction, we decided to see if removing the phone number field would increase the likelihood of a visitor to make a gift. This field was already optional but the hypothesis was that by simply having this field as an option, it created mental friction in the mind of the visitor.

Research Question

Will removing the optional phone number field increase donor conversion?


C: With Phone Number
T1: No Phone Number


 Treatment NameConv. RateRelative DifferenceConfidence
C: With Phone Number 11.8%
T1: No Phone Number 11.6%-1.6% 16.6%

This experiment has a required sample size of 215,825 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

After running for two weeks, we were able to determine that the phone number field did not add a significant level of friction to the donation process. This is actually great news for the college since they are starting up a phone program and collecting donor phone numbers is now becoming a priority. It is good to know that donor conversion does not suffer by simply having it available.

Experiment Documented by NextAfter

Question about experiment #6086

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