What was at stake.
Post-iOS 17 and the long fade of third-party cookies, FNP's attribution had degraded to the point where the CFO was making budget decisions on platform-reported numbers — which never reconciled to bank deposits.
Each ad platform claimed 70% of conversions. The math literally didn't add up.
What we did.
We deployed a server-side GTM container, wired in CAPI for Meta and Enhanced Conversions for Google, and built a unified event schema across all paid channels.
On top of that we layered MMM (Bayesian, refreshed monthly) and quarterly incrementality testing — geo holdouts on the largest spending channels. The MMM gives the CFO a believable spend-allocation view; incrementality keeps it honest.
Output goes into a single attribution dashboard that platform-reported numbers feed into, but don't dictate.
What changed.
100% of conversions tracked server-side with under ±4% MMM error against bank-deposit reconciliation. CFO signs off on quarterly spend plans grounded in this stack.