Attribution windows are the quiet dials behind every channel report. Move them a few days and the ranking of your channels can flip. Yet most teams never touch them, and many do not know the defaults their tools ship with.
The three windows
- Click window (default 28 days): how long after a click a conversion can still be credited to it. Clicks are strong intent signals, so the window is generous.
- Impression window (default 1 day): how long an ad that was merely shown can claim credit. Impressions are weak signals, so the window is tight.
- View-through window (default 7 days): a middle ground for video and rich media that was watched but not clicked.
These defaults are not arbitrary. They mirror the shapes used across Adjust, AppsFlyer and Branch, which is why they have become an informal industry standard.
Why the window changes the story
A longer click window gives credit to channels that plant intent early, such as search, influencer, and referral. A shorter impression window strips credit from channels that flood cheap impressions and hope something sticks. So the windows are not neutral bookkeeping; they encode a point of view about which touches deserve credit.
The safest way to read an attribution report is to know the windows behind it before you read the numbers.
Make them a read-time setting, not a migration
The mistake is baking windows into the data pipeline, so that changing them means re-processing history. The better design keeps the raw touchpoints intact and applies the windows at query time. Then a marketer can compare 7-day vs 28-day click attribution side by side in seconds and see exactly how sensitive each channel is to the assumption, without a single database write.