Global Christian Relief

How Meta Campaign Optimization Goals Affect Donor Acquisition Costs

Experiment ID: #201984

Global Christian Relief

Experiment Summary

Timeframe: 12/19/2025 - 01/04/2026

Global Christian Relief (GCR) has a strategic priority to grow its email subscriber base as a pathway to long-term donor growth. While acquiring email addresses at a low cost is important, the team recognizes a core tension: not all subscribers are equally likely to become donors. This experiment is designed to explore how acquisition strategy influences downstream donor quality, not just volume.

Specifically, this test examined whether Meta’s ad optimization goal affects the cost-effectiveness of acquiring future donors through a content offer funnel. The central question is whether optimizing campaigns for email sign-ups (names) or for donations (purchases) ultimately leads to lower donor acquisition costs.

The goal of this experiment is to determine whether optimizing earlier in the funnel for volume (email sign-ups) or later in the funnel for intent (donations) results in more cost-effective donor acquisition over time. The findings will inform how GCR balances scale and quality in its paid acquisition strategy and how it approaches list growth as a driver of sustainable fundraising.

To test this, GCR promoted a single content offer through Meta ad properties, including Facebook, Instagram, and Threads. Ads were duplicated across two campaigns that were identical in creative, audience, and spend, with the only variable being the Meta Pixel optimization goal. One campaign was optimized for email sign-ups (email optimization, serving as the control), while the other was optimized for donations (purchase optimization, serving as the treatment).

The audience for both campaigns was built using a combination of existing GCR donors and a lookalike audience derived from that donor data, ensuring the ads reach people with a higher likelihood of alignment and potential generosity. Ad spend was split evenly between the two campaigns to allow for a fair comparison.

Research Question

We believe that optimizing Meta ad campaigns for donations rather than email sign-ups for prospective supporters reached through Meta Ad campaigns will achieve more cost-effective donor acquisition because signals of high intent help ad platforms prioritize users who are more psychologically ready to give, not just willing to exchange an email address.

Design

C: Control

T1: Treatment

Results

	Treatment Name	Conv. Rate	Relative Difference	Confidence
C:	Control	0.03%
T1:	Treatment	0.47%	1,480.2%	99.5%

This experiment has a required sample size of 502 in order to be valid. Since the experiment had a total sample size of 8,599, 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
× 1,480.2% increase in conversion rate
× 0% increase in average gift

Key Learnings

Optimizing Meta campaigns for donations rather than email sign-ups led to significantly stronger donor outcomes. While the email-optimized campaign generated more overall traffic, the purchase-optimized campaign produced more than four times the donation conversion rate (0.47% vs. 0.03%) and drove 9 of the 11 total donations, despite receiving fewer impressions and a smaller sample size.

The relative difference between the two approaches was substantial: the purchase-optimized campaign outperformed the email-optimized campaign by 1,480%, with a 99.4% level of statistical confidence, exceeding the threshold required for a valid result. This indicates that the observed performance difference is highly unlikely to be due to chance.

We also measured the Gross Cost Per Donor (GCPD) as a key metric in this test. The email optimized campaign yielded a GCPD increase of 347%—further proof that optimizing for donations in Meta Ads campaigns is a much more efficient use of ad spend than optimizing for more top-of-funnel conversions.

These results suggest that Meta’s optimization signals meaningfully influence who is delivered into the funnel, not just how many people enter it. When the platform is instructed to optimize for donations, it appears to prioritize users who are psychologically closer to making a financial commitment, even when the initial interaction is a content offer rather than a direct donation ask. In contrast, optimizing for email sign-ups likely attracts lower-intent users who are willing to exchange an email address but are less prepared to give.

Importantly, this test highlights a key tradeoff in list growth strategy. While optimizing for email acquisition may reduce cost per subscriber and increase list volume, it can significantly dilute downstream donor quality. For Global Christian Relief, where the ultimate goal is list growth, optimizing for higher-intent actions earlier in the funnel is more effective.

The implication for future campaigns is clear: when donor acquisition is the primary objective, optimizing paid media for donations—even within an indirect, content-driven funnel—can yield fewer but substantially more valuable supporters. This finding supports a shift away from volume-first acquisition metrics and toward optimization strategies that reflect true donor intent and long-term fundraising value.

Open questions remain around scale and efficiency: how this approach performs at higher spend levels, whether similar patterns hold across different offers or audiences, and how email engagement and lifetime value differ between cohorts acquired under each optimization goal. These areas represent strong candidates for follow-up testing.

Experiment Documented by Ardee Coolidge

Question about experiment #201984

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