Turning Incrementality Tests Into Action That Makes You Money

Incrementality tests are “in”… but the real problem is what you do after the read.

In this episode, Taylor sits down with Olivia Kory (Chief Strategy Officer at Haus) and George Davis (CMO at Cozy Earth) to unpack the messiest part of modern measurement: operationalizing incrementality when results swing, channels conflict, and “platform ROAS” can’t be trusted.

If you’ve ever asked:

• “Our holdout came back way lower than Meta… now what?”

• “Why don’t test results replicate month-to-month?”

• “How do I actually use an incrementality factor in real budget decisions?”

• “If everything is under 1.0 iROAS… should we cut spend or keep investing?”

…this one is for you.

What we cover

• Why incrementality requires a holdout (and why “spend up / spend down” isn’t enough)

• The replication problem: why results change even with “clean” tests

• The gap between measurement and optimization (platforms optimize for attribution, not incrementality)

• How operators use incrementality factors without letting them become a blunt instrument

• Why channel vs. channel is often the wrong fight (and why profit thresholds matter more)

• iROAS → IMR (Incremental Marginal Return): a more intuitive way to compare performance

• Budget cadence: daily realities vs monthly allocation decisions

• Long-term effects, “adstock” claims, and why post-treatment windows matter

• Practical levers that can improve results: creative, account structure, exclusions, distribution expansion (Amazon/retail)

Got a weird incrementality result? Drop it in the comments. We’ll let you know what we’d do next.

Read this next: CTC Core Methodology Series: Marketing Measurement - https://bit.ly/4tW2JwF

Show Notes:

• Axon is offering $5K ad credit when you spend $5K. Go to https://axon.ai/en/ctc to set up your first campaign.

• Explore the PROPHIT System: http://prophitsystem.com

• The Ecommerce Playbook mailbag is open — email us at podcast@commonthreadco.com to ask us any questions you might have