The Ecommerce Playbook Podcast

Hosted ByTaylor Holiday & Richard Gaffin

2020 transformed the world of ecommerce forever. For the modern DTC brand, the rewards have never been greater. But the waters have also never been choppier, and the way forward has never been more uncertain. So how do you navigate this dangerous new reality? No matter how you do it, you’d better not do it alone. That’s where the Ecommerce Playbook Podcast comes in — join Common Thread Collective’s Taylor Holiday & Richard Gaffin as they bring you guiding insights from across CTC’s portfolio of growing DTC businesses. Whether you need a clear view on the macro issues affecting the world.

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The Ecommerce Playbook | The Measurement Gap: iROAS, Geo Holdouts, and Progressive Truth

July 2, 2026 The Ecommerce Playbook Podcast 00:23:07
The Ecommerce Playbook Podcast
The Ecommerce Playbook Podcast
The Ecommerce Playbook | The Measurement Gap: iROAS, Geo Holdouts, and Progressive Truth
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Your platform ROAS is not the truth. It’s a story your attribution tool tells you. Luke Austin, breaks down exactly how CTC approaches marketing measurement — and why the gap between platform-reported numbers and actual incremental revenue is where most brands make their worst capital allocation decisions.

This is Part 3 of the CTC Canon Series — our codified methodology across the core disciplines of ecommerce growth. In this episode, Luke covers the full measurement framework: why geo holdout tests are the gold standard, how CTC’s database of hundreds of incrementality tests gives every new brand a head start, and what it means to build “progressive truth” over time instead of chasing a single source of truth.

Topics covered:

  • Why media efficacy is always in flux — and why any system that treats it as fixed is lying to you

  • The measurement gap: reality vs. fiction, and how to move closer over time

  • Geo holdout tests explained — how they work, why they’re the gold standard

  • CTC’s incrementality benchmarks by channel: Facebook acquisition (1.14x iROAS), Google Branded (0.27x iROAS), and more

  • Why Google branded search dramatically over-reports ROAS

  • How iROAS normalization enables true apples-to-apples channel comparison

  • The three-stage framework: aggregate benchmark, individual test, accumulated median

  • Why iROAS is always subordinate to contribution margin

Show Notes: