What is an attribution window?
How does an attribution window work?
A window has two parts. A click window covers purchases after someone clicks an ad. A view window covers purchases after someone sees an ad without clicking, known as a view-through conversion.
Write the window out in full. For example: "7-day click, 1-day view". Without it, a number has no clock attached.
Why do Meta and my shop disagree?
Different tools use different windows. Some count clicks only. Others count clicks and views. So the same sale can be credited in one tool and missing from another. The tools are not always wrong. They are answering different questions.
A longer window gives ads credit for more sales. It does not mean the ads caused more sales. Credit is attribution. Cause is a different question. That is why ROAS always needs its window stated.
Platforms also name it differently: GA4 talks about a lookback window, Google Ads about a conversion window. Our convention: compare numbers across platforms only on the same window. If that is not possible, say so next to the number.
For ZFD: We do not assume a platform always over-credits or under-credits. We ask what the numbers look like on one shared window, and where it matters, check them with a test.
Worked example
Easily confused with
Attribution window vs View-through conversion
A conversion credited to an ad that was seen but not clicked. It is one part of a window, not the window.
Attribution window vs Attribution
The rule for splitting credit. The window limits how far back that rule looks.
Attribution window vs Incrementality
What the ads caused beyond what would have happened anyway. A window can change the credit without changing the cause. For how methods differ, see MMM vs MTA vs incrementality tests.
FAQ
Does a longer attribution window mean better results?
No. It means more sales are credited to ads. Some of them would have happened anyway.
Which attribution window should we use?
Pick one, write it down and use it everywhere you compare. Choose it by how long your customers take to decide, and check that against your own order data.
Does the window change what actually happened?
No. Orders are the same. The window only changes which ad gets credit.
Sources
Let’s find what’s actually working.
Next step. Check what your numbers look like on explicit assumptions. Use the Is your ROAS real? calculator.