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Google Just Made Incrementality Testing Open Source. Meridian GeoX Changes the Measurement Game.

Google is not just giving away a measurement tool. It is trying to become the default infrastructure for how advertisers prove value across channels.

Filip Ivanković··2 min read
2 min read

Google has launched two measurement tools that could reshape how advertisers prove their spend is working. Meridian GeoX is a free, open-source tool for running geo-based incrementality experiments. Meridian Studio is an enterprise platform for managing marketing mix models at scale on Google Cloud.

GeoX works by comparing ad performance across geographic regions to isolate incremental lift. It has been in testing in select markets since 2022. The open-source release means any advertiser with basic analytics capability can now run the same kind of incrementality experiments that previously required dedicated measurement teams and expensive third-party vendors.

Since 2022

Google has been testing GeoX in select markets. The open-source release now makes geo-based incrementality testing available to any advertiser.

Meridian Studio sits on top of this as the enterprise layer. It provides cloud-powered infrastructure for running complex marketing mix models with multiple data sources, automated modelling and scenario planning. Think of it as the managed version for teams that want incrementality at scale without building their own data science stack.

Why it matters

Incrementality testing has been the gold standard for measurement but practically inaccessible to most advertisers. The cost, complexity and data requirements meant it was reserved for brands spending millions per month. GeoX lowers that barrier significantly.

The strategic angle is also important. Google has a vested interest in advertisers proving that Google spend drives incremental outcomes. Open-sourcing the tool positions Google as the neutral measurement layer, even though it is also the platform being measured. That tension will not go away, but the tooling itself fills a real gap.

For Australian advertisers, geo experiments are particularly useful given the natural geographic segmentation of state-based markets. Running a test across NSW and Victoria with holdout regions is straightforward and the population sizes are large enough for statistical significance.

What to do about it

Download Meridian GeoX and run a pilot incrementality test on your highest-spend channel. Start with Google Ads if that is your largest platform.
If you are spending over $50K per month on paid media, explore Meridian Studio for ongoing MMM. The cloud-based approach removes the need for in-house data science.
Use geo experiments to validate your attribution model. If your last-click or data-driven attribution says one thing and incrementality says another, trust the experiment.
Test incrementality on non-Google channels too. GeoX is open source and platform-agnostic. Run it against Meta, TikTok or programmatic spend.
Brief your CFO on the results. Incrementality data speaks the language of finance in a way that click-based metrics never will.

Google just made the most credible form of ad measurement free. The advertisers who use it will make better decisions. The ones who ignore it will keep guessing.

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Filip Ivanković
Filip IvankovićFounder, New Rebellion

10+ years leading performance marketing across agencies and in-house teams in Australia. Writes about the gap between marketing activity and commercial outcomes, and what it takes to close it.

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