Conversion Window
The time period after ad exposure during which conversions are counted.
Conversion Window is a testing & measurement concept that ecommerce teams touch every week, usually without agreeing on a definition first. This page sets out what it means, how to apply it at catalog scale, what to measure, and where it breaks.
Definition
The conversion window is the lookback period — commonly 1, 7, or 28 days after click or view — during which the platform attributes conversions to an ad.
Why it matters
Different windows produce dramatically different ROAS numbers for the same campaign. Comparing across windows is one of the most common reporting errors.
Conversion Window in practice
The conversion window is the lookback period — commonly 1, 7, or 28 days after click or view — during which the platform attributes conversions to an ad. Measurement concepts exist because ad platforms report the results they can see, and that is not the same as the results you caused. The gap shows up whenever a channel reports growth that the P&L never receives. Knowing which question a method answers keeps you from over-reading a dashboard. Read it next to Attribution, ROAS (Return on Ad Spend).
How to get it right
Decide the question, the metric and the stopping rule before launch. Change one variable per test, hold budget and audience constant, and let the test run through at least one full purchase cycle. Write the result down — including the null results, which are the ones teams repeat most often.
What to measure and watch
Check whether you have the sample size to detect the effect you care about before declaring a winner; small differences need far more data than most accounts generate in a week. Cross-check platform-reported results against a holdout or an aggregate model when the stakes are large. Why this matters commercially: Different windows produce dramatically different ROAS numbers for the same campaign. Comparing across windows is one of the most common reporting errors.
Where Conversion Window sits in an agentic creative workflow
Testing at any useful rate needs supply. Xeli produces clean, single-variable variants across your catalog — same layout, one changed element — so tests are properly controlled and the production queue is never the bottleneck. In the context of testing & measurement, that means the concept stops being something a person re-applies by hand every campaign and becomes a rule the system enforces on every asset it produces.
Failure modes worth naming
The recurring problems are predictable: comparing 7-day-click roas to 28-day; setting windows longer than the real decision cycle; not documenting the window in every report. Each of these is a process gap rather than a knowledge gap — which is why the fix is usually a checklist, a template or an automated rule instead of more training.
Common mistakes
- ✕Comparing 7-day-click ROAS to 28-day.
- ✕Setting windows longer than the real decision cycle.
- ✕Not documenting the window in every report.