Platform-reported conversions and analytics-reported conversions are measuring different events. Here is how we reconcile them before a client ever sees a number.
Every agency has had this call. The client is looking at the Google Ads interface and seeing 84 conversions. Your report says 61. Nobody is lying and nobody can explain it in the ninety seconds before the client decides the reporting is untrustworthy.
The gap is almost never an error. It is two systems measuring different things and being asked to agree.
Attribution model. Ad platforms credit themselves generously and by default attribute a conversion to the click that started the journey. Analytics tools typically credit the last non-direct source. The same sale gets assigned to different places.
Attribution window. A platform will happily count a conversion that happened 29 days after a click, and it will book it against the date of the click, not the date of the sale. Analytics books it on the day it happened. In a month with uneven spend, that alone moves the number.
What counts as a conversion. Most accounts we inherit have three or four conversion actions firing, and at least one is a proxy — a page view on a thank-you URL that also fires on a refresh, or a phone-click that never connected.
Deduplication. If the same purchase fires through both a pixel and a server-side event without a shared identifier, it counts twice.
On onboarding we pick one definition per account and write it down. Not the most flattering one — the one the client would still agree with if they audited it.
Then we turn off or rename every conversion action that is not that definition, so nobody can accidentally report on it. Proxy conversions get a "secondary" label and are excluded from the headline number.
The monthly report states the definition in plain language at the top. It sounds pedantic. It ends the argument permanently.
Reconciling honestly almost always makes your numbers look worse than the platform interface. That is a conversation worth having once, early, on your terms — rather than the version where a client discovers the discrepancy themselves and wonders what else is inflated.
Send the shape of what you are carrying — how many accounts, which channels, where it hurts. We will come back with specifics.