How budget optimization impacts donor conversion through paid Facebook ads Experiment ID: #20751

The Missionary Oblates of Mary Immaculate

The Missionary Oblates of Mary Immaculate are a Roman Catholic congregation of priests and brothers founded after the French Revolution by St. Eugene De Mazenod to work among the poor. Today there are nearly 4,000 missionaries working in more than 60 countries around the world.

Experiment Summary

Timeframe: 3/7/2020 - 4/7/2020

The Missionary Oblates run a significant number of paid Facebook campaigns in an effort to acquire new names and donors to their organization. Over the past year, they have learned a lot of optimization tactics through testing that have allowed them to increase their conversion rate in this channel. Recently they learned that using a “Lifetime” budget instead of a “Daily” budget in Facebook for the campaign they could increase donor conversion. Without having data behind the ideal length of time for that “Lifetime” budget, they set these campaigns to a four-week timeline and then would reset the budgets. Wanting to know and test into if this length of time was ideal, they set up a test that used the monthly lifetime budget for the control and developed an identical campaign that used a longer lifetime budget of four months. They also took the monthly spend and multiplied that by four (four month timeline) to get their budget for their treatment campaign.

Research Question

Can we increase donor conversion by optimizing our Facebook campaign to a longer timeframe using a larger budget?


C: Lifetime Monthly Spend
T1: Lifetime Extended Spend


Treatment Name Conv. Rate Relative Difference Confidence
C: Lifetime Monthly Spend 0.11%
T1: Lifetime Extended Spend 0.18% 55.5% 97.8%

This experiment has a required sample size of 28,582 in order to be valid. Since the experiment had a total sample size of 76,877, 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
× 55.5% increase in conversion rate
× 0% increase in average gift

Key Learnings

Over the four week period the test ran, we were able to validate the results and increase donor conversion (instant) by 55%! What is interesting is that even though Facebook had a much larger budget for a longer time period, the increase in donor conversion was not due to Facebook just simply increasing the volume of spend. The treatment version only spent an additional $140 than the control. Our hypothesis is that by giving Facebook a longer period of time with a larger budget it has more flexibility in how it optimizes the campaign.

We will continue to monitor this extended lifetime budget since the results from the experiment were only four weeks into the four month spend of the campaign. This will have a significant impact on the number of new donors acquired through this campaign.

Experiment Documented by...

Courtney Gaines

Courtney is a 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.