Attribution Windows and Why They Change Reported Performance

Two platforms reporting on the same campaign can disagree by a wide margin without either of them being wrong. The difference is usually the attribution window, and understanding it prevents a lot of unnecessary argument.

What a window actually decides

An attribution window sets how long after a click or view a conversion may still be credited to that interaction. A seven-day click window is standard for many retail advertisers, while longer windows suit considered purchases with longer decision cycles. Changing the window changes the reported total without changing a single order.

Platforms will overlap by design

If a customer sees a social ad on Tuesday, searches on Wednesday and buys on Thursday, both systems have a legitimate claim. Each platform reports its own credit, so the sum of platform-reported conversions will exceed the number of orders. This is expected behaviour, not a tracking error.

Choose one reporting source of truth

Decide which system governs the business decision and use the others for diagnosis. For most advertisers the source of truth is the order data in the back office, because it reflects what was actually paid for.

Use platform data to explain, not to total

Platform reporting remains valuable for understanding which creative and which audience drove a change in behaviour. Treating it as a contribution signal rather than as an accounting total keeps both uses intact.

Keep windows stable within a comparison

When comparing two periods, keep the attribution window identical. Changing the window between the two periods makes the comparison meaningless, which is one of the most common ways a report misleads its own author.