What is attribution?
Nicklas Segatz Mortensen · Growth Hacker · Fractional CMO · Meta Ads Nerd · 8 July 2026 · 6 min.
Definition
Attribution is the method that distributes the credit for a conversion across the touchpoints the customer met along the way. The model decides which channel gets the credit — and therefore where budget flows.
Also called: Attribution modeling, Attribution model, Crediting
Sådan virker det
Attribution fordeler æren for ét salg ud på de touchpoints, kunden mødte. Last-click giver alt til det sidste — de øvre kanaler ser svage ud. Ingen model er sand; totalen (MER) og inkrementalitet afgør sandheden.
01The models and their bias
Last-click gives all the credit to the final touchpoint — typically brand search or retargeting, which makes the upper-funnel channels look weak. First-click does the opposite. Data-driven and position-based models spread the credit, but still build on data that has grown patchier and patchier after iOS updates and cookie restrictions.
No model is “true”. They're lenses, not verdicts. The danger is treating the platform's attributed ROAS as reality and cutting the very channels that actually drive demand.
02How we use attribution
We use attribution for direction, not for judgment. For the final budget decision we weigh it against MER (the blended total) and incrementality tests. Attribution says “something seems to be happening here” — incrementality says “something is genuinely happening here”.
A solid server-side setup makes attribution less patchy by rebuilding the signals the browser has shut down. But even perfect data doesn't change the fact that attribution and incrementality are two different questions.
03Attribution windows: where the number gets inflated
The model itself is only half of it; the window is the other. Meta reports on 7-day click and 1-day view by default — so the platform takes the credit if someone clicks and buys within a week, or just sees the ad and buys within a day. View-through conversions are especially generous: many of them would have happened anyway. Google counts just as broadly. The longer and more inclusive the window, the more the attributed ROAS is inflated.
That's why two accounts with identical results can report wildly different ROAS, purely because they have different attribution settings. It's also why the sum of every channel's attributed revenue often exceeds what actually came in: each measures in its own silo with its own generous window.
Our approach: use one consistent window to compare over time (so trends are real), but never make budget decisions on the attributed number alone. The final verdict belongs to MER and incrementality tests — the only measures that can't be inflated by a window.
Frequently asked questions
Which attribution model is best?+
There's no single best model — each has a built-in bias. Smarter than picking one is reading several together and validating with blended numbers (MER) and incrementality tests.
Why do Meta and Google show higher numbers than my store?+
Because each platform credits itself with sales that other channels also saw — they double-count. So the sum of the platforms' reported revenue often exceeds the actual revenue in your store.
Related terms
Glossary
What is incrementality?
Incrementality is the added effect a marketing effort creates: the sales that happened only because the ad ran. Sales you'd have gotten anyway aren't incremental — whatever the platform credits.
Read the entry →Glossary
What is server-side tracking?
Server-side tracking sends conversion events from your own server (e.g. via a server-side Google Tag Manager container and Meta's Conversions API) instead of from the user's browser — so data isn't lost to ad blockers, cookie restrictions and iOS limitations.
Read the entry →Glossary
What is MER?
MER (Marketing Efficiency Ratio) is your total revenue divided by your total marketing spend across every channel. It ignores the platforms' own attribution and shows how efficiently the whole marketing machine is working.
Read the entry →Glossary
What is ROAS?
ROAS (Return on Ad Spend) is the revenue generated by ads divided by ad spend. A ROAS of 4 means €4 in revenue for every ad euro — but says nothing about what you actually keep.
Read the entry →
Nicklas Segatz Mortensen
Growth Hacker · Fractional CMO · Meta Ads Nerd at Oaksmond
Growth hacker and fractional CMO with 10+ years' experience and hundreds of millions in managed ad spend behind him. Background from larger Danish and international scale-ups, and from the agency world.
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