An attribution window is the period a platform looks back over to decide whether an ad deserves credit for a conversion. Widening it credits more conversions to the same spend, so reported performance improves without anything actually changing — which is why comparing periods measured on different windows is meaningless.
What do click and view windows mean?
A click window credits the ad if someone clicked it and converted within the period. A view window credits it if someone merely saw it and converted later without clicking.
View-through credit is the more contested of the two, because the evidence is weaker. The impression happened; whether it caused anything is an assumption the platform is making on your behalf.
How much does the window change the numbers?
Enough to reverse a conclusion. A longer window sweeps in conversions that occurred days after the interaction, so the same campaign reports more conversions, lower cost per acquisition and higher return on ad spend.
Nothing about the campaign improved. This is why a change in window has to be recorded in the report — a jump in performance with no corresponding change in activity is usually a settings change.
Which window should you use?
One that matches how long your customers actually take to decide, then leave it alone.
- Short consideration purchases — a short click window is usually honest.
- Considered or high-value purchases — a longer window reflects reality.
- Any comparison over time — the same window on both sides, without exception.
What breaks when windows differ across platforms?
Cross-channel comparison. If one platform credits on a seven-day click and another on a twenty-eight day click with view-through, their conversion counts are not comparable, and adding them together produces a total that double counts.
The practical answer is to compare each channel against its own history rather than against each other, and to say in the report that the definitions differ.
Frequently asked questions
- What is the default attribution window?
- It varies by platform and changes over time, which is itself a reason to check rather than assume. Record the window in use alongside the figures.
- Does a longer window mean better attribution?
- It means more generous attribution. Whether it is more accurate depends on whether your customers really do convert that long after seeing an ad.
- Do attribution windows affect organic reporting?
- Not directly. Organic reach and engagement are counted when they happen. Windows matter for conversions, which is why paid and organic figures should not be summed casually.