Problem
Paid media performance looked strong in-platform, but leadership lacked confidence in what was actually incremental. Budget decisions were being made off correlation instead of causation.
Approach
Designed a geo-holdout framework across matched markets, paired it with Bayesian media mix modeling, and used the two methods together to validate true channel contribution before reallocating spend.
Key insight
Reported ROAS was materially overstated in at least one major channel, and the biggest wins came from shifting budget toward channels that were undervalued by platform reporting.
Business impact
The new measurement system redirected budget with more confidence, reduced wasted spend, and gave leadership a defensible basis for growth planning instead of relying on dashboard optics.