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Does Meridian Favor Google?

Mathieu Lepoutre
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Published on
2/10/2025
In this article, Mathieu Lepoutre, Global Media Offers Director at fifty-five, explores whether or not Meridian, Google's open-source Marketing Mix Model (MMM), favors the tech giant's products.

WHY GOOGLE OFFERS MERIDIAN'S CODE FOR FREE

Does Meridian favor Google? The question is a pertinent one – why would Google provide an open-source code for free to help advertisers make media trade-offs, if not to benefit its own advertising products? Especially since by offering an open-source code, Google relinquishes access to its competitors' data and the results of the analysis. Therefore, access to data is not what motivates the Mountain View giant.

This suspicion of favoritism is entirely understandable, especially since analyses conducted via Meridian seem to systematically favor Google's advertising levers. Indeed, we have observed returns on investment (ROI) that are often above average, which encourages a reallocation of budgets towards Google's advertising solutions. At fifty-five, we choose not to disclose specific figures because, unlike some of our competitors, we do not rely on our clients' data and results to market benchmarks.

We can therefore legitimately suspect Google of intentionally favoring its products through Meridian to capture new advertising budgets and grow faster than the advertising market. But what is the reality?

HOW FIFTY-FIVE VERIFIED THE NEUTRALITY OF MERIDIAN

To determine this, fifty-five first audited the open-source code to ensure its neutrality. We are not the only agency to have conducted this verification; to date, no alerts have been raised. Beyond the code, we act as a trusted third party by being agnostic and completely transparent in the configuration of this algorithm. Furthermore, nine months before the official launch of Meridian, we had the opportunity to be commissioned by Bouygues Telecom to test Meridian in advance and compare it with Robyn, another open-source model developed by Meta. The two models yielded very comparable results.

We do not doubt the neutrality of the solution, provided it is configured correctly.

Secondly, because trust does not exclude control, fifty-five systematically conducts the following simple test: once the model is completed, we make an exact copy and change the media labels, replacing, for example, the label "YouTube" with "Meta," along with various substitutions. 

Pictured: Examples of substitutions used

In both versions, the results are strictly identical. Performance does not depend on the name of the lever.

CONCLUSION

So, to the question, "Why does Google expend so much energy to provide a free open-source code that helps advertisers make media trade-offs, without any control lever?" The answer may simply be that Google believes in the performance of its products, which AI increasingly drives. It is a risky bet, but so far, one that has proven highly profitable.

To learn more about Meridian and how to leverage this open-source asset for your organization, please don't hesitate to contact us!

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