Every platform over-claims
If you add up the conversions each ad platform reports, you'll routinely get 150–200% of your actual revenue. Each platform uses a different attribution window and model, and each has an incentive to claim credit. Managing a business to those numbers is managing to fiction.
Build one number you trust
The fix is a single source of truth: server-side conversion tracking that counts real orders in your database, blended with marketing spend from every channel. From that you derive MER (revenue ÷ spend) and channel-level contribution. It's not as flattering as platform ROAS, but it's the number your CFO can act on.
How to start
You don't need a data warehouse on day one. Start with server-side events piped to a spreadsheet, reconcile weekly, and report blended efficiency alongside platform metrics. As you scale, formalise it into a dashboard — but don't wait for perfection to start making better decisions.
The platform numbers are for optimising within a channel. The blended number is for running the business. Don't confuse them.
Once leadership trusts the blended number, budget conversations get dramatically shorter — and the marketing team stops defending its existence every quarter.
