This Agency Abandoned MTA, Here's Why

There’s a particular kind of vertigo that comes from watching a podcast you started get better without you. I launched the Ecommerce Braintrust podcast back in 2017, and while I’m no longer running it, I still listen because the team at Acadia is in the trenches every day doing the work.A recent conversation between my old Acadia colleagues on measurement really got me thinking about a question I hear from brands all the time: if every advertising platform says it’s winning, why don’t the business results reflect that? When Meta, Google, Amazon and retail media networks all claim credit for conversions, the numbers can quickly become impossible to reconcile. In this episode, I share snippets from a recent Ecommerce Braintrust episode that dig into the idea of “engine inflation,” why multi-touch attribution is struggling in 2026, and what brands should be using instead to understand what is actually driving incremental growth.This episode is sponsored by GrowthLoopTimeline[00:00] - The measurement problem every advertiser is wrestling with: when every platform claims to be winning, why don't the business results add up?[01:45] - Introducing “engine inflation” and why platform-reported revenue can exceed actual business revenue.[03:56] - Why multi-touch attribution isn't coming to save us and why Acadia has moved away from MTA.[04:52] - The three-pillar measurement framework: media mix modeling, incrementality testing, and platform optimization.[06:15] - Why the growth of retail media networks makes a holistic view of total media spend increasingly important.[08:34] - Why measuring Amazon and Walmart simply by retail media network and ad type can produce the wrong conclusions.[09:46] - How defensive branded search can look incredibly efficient while doing very little to drive incremental growth.Links & ResourcesListen to the full Ecommerce Braintrust episode: The 2026 Measurement Crisis: Why Your Media Efficiency is Probably a Lie With Sally Kazin and Ross Walker - Episode 438Subscribe to Ecommerce Braintrust on Apple PodcastsFollow Sally Kazin, Head of Analytics @ Acadia, on LinkedInFollow Ross Walker, Head of Retail Media @ Acadia, on LinkedInRead my related articles:Retail Media's Measurement Problem: It's Not Just the Retailers'Not 100% altruistic': ad measurement veteran on what retail media is really optimizing forAs Retail Media Spending Soars, Brands Face A Measurement CrisisThe Other Side of the Story: Why Retailers Struggle with Media Measurement & StandardizationCheck out Basket Case, a project I’m part of with The Drum and QSIC, an irreverent and lively podcast series where we talk shop.I'm sharing comedy skits on Instagram about retail media! Follow along: @retailmediabreakfastclubSubscribe to Retail Media Breakfast Club's daily newsletterFollow Kiri Masters on LinkedIn