SlackWhat a window is
An attribution window is the time after a click or a view in which a platform may credit an order to an ad. A longer window credits more orders, and so does counting views as well as clicks.
Why it matters in a report
- A change in window changes ROAS without any change in performance.
- Platforms use their own defaults, so side by side numbers are not like for like.
- Reports that mix windows make month on month comparisons misleading.
How to handle it
- Pick one window per platform and keep it for the whole client relationship, unless you restate the history.
- Write the window next to every ROAS figure.
- Use MER as the headline, because it does not depend on a window.
When a test is better than a window
A window assigns credit but does not prove cause. For a decision that matters, such as cutting a channel, use a holdout test or a similar experiment, and state its design and period.
A definition and a made-up example are in the attribution window glossary entry.
