How XXL Nutrition proved Meta’s incremental impact on Google Search and purchases
A 30-day geo-holdout test with Billy Grace showed Meta driving incremental purchases for XXL Nutrition and lifting Google branded search by nearly 10%.
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E-commerce (Sports Nutrition)
XXL Nutrition, the biggest Dutch sports nutrition brand, wanted to gain a deeper understanding of its advertising impact. Together with Billy Grace, the brand conducted a 30-day geo-holdout test, confirming that Meta advertising not only drives incremental purchases but also influences Google Search activity.
Challenge: Understanding Meta’s incremental impact
As one of XXL Nutrition’s largest advertising channels alongside Google Ads, Meta has long played an important role in the brand’s marketing strategy.
The team was already using Billy Grace’s attribution insights to understand how different channels contributed to conversions. They wanted to build on these insights by measuring Meta’s incremental effect, in other words how much additional traffic and how many purchases were actually generated by its advertising.
By combining attribution with incrementality testing, XXL Nutrition aimed to gain a more complete understanding of Meta’s contribution and make more informed decisions about its marketing investments.
Approach: A 30-day geo-holdout test
To measure Meta’s incremental contribution, XXL Nutrition used Billy Grace’s Incrementality Testing solution to conduct its first incrementality experiment.
All Meta campaigns were paused in two Dutch provinces, Gelderland and Overijssel, for 30 days, while advertising continued as usual in the control regions.
By comparing performance between the test and control regions, Billy Grace measured Meta’s incremental effect on website sessions, Google Search activity and purchases.
The experiment focused on sessions to capture Meta’s broader influence on website traffic, while also tracking its impact on purchases over time.
Results: Meta’s impact extends beyond its own platform
The experiment confirmed that Meta advertising was generating incremental value for XXL Nutrition, not only through its own platform but also by influencing activity on Google Search.
One of the most interesting findings was the effect on Google branded search. When Meta advertising was paused in the test regions, branded search activity was also affected, revealing that Meta contributed to demand captured through Google.
The test also identified an incremental effect on non-branded Google Search sessions, further demonstrating Meta’s influence beyond its own platform.
For XXL Nutrition, this cross-channel effect was a valuable additional finding. While the relationship between social advertising and search behaviour made sense to the team, it wasn’t the primary outcome they had expected to uncover.
The experiment also revealed an important pattern in purchase behaviour. While the effect on website sessions appeared earlier, the impact on purchases became more visible after approximately two weeks.
This highlights why the duration of an incrementality test matters. Advertising can influence customer behaviour before its full impact on purchases becomes visible.
From measurement to more confident marketing decisions
For XXL Nutrition, the results provided additional evidence supporting Meta’s role in its marketing strategy.
By confirming Meta’s incremental contribution, the experiment strengthened the team’s confidence in continuing to invest in the channel.
The team can now evaluate Meta through both attributed conversions and its measured incremental contribution to traffic, search activity and purchases.
Results
+9.81% incremental lift in Google branded search sessions
+4.01% incremental lift in total sessions
+4.95% incremental lift in purchases
Key Takeaways
Insights based on XXL Nutrition’s test experience
- Meta’s impact goes beyond Meta. Advertising on Meta can generate incremental demand captured through other channels, including Google Search.
- Incremental impact takes time to emerge. The effect on purchases became more visible after approximately two weeks, showing why test duration matters.
- Incrementality testing supports confident decisions. Measuring a channel’s incremental contribution can help marketers validate their investments and inform future budget allocation.
With greater confidence in Meta’s incremental contribution, XXL Nutrition is now looking to extend incrementality testing to other advertising channels, building on its existing measurement approach to make more informed marketing decisions.
