What is an attribution window?

Click windows and view windows

There are normally two, and they are set separately because they represent different strengths of evidence.

A click-through window applies after a user actively clicked. Because a click is a deliberate act, the window is usually generous — 7 days is a common default, 30 days in considered-purchase categories.

A view-through window applies after an impression the user did not click — see view-through attribution. The evidence is far weaker, so the window is short: 24 hours is typical, and anything longer starts crediting coincidence.

How window length changes the numbers

Lengthening a window never reduces attributed conversions and almost always increases them, because more of the ambient conversion rate falls inside it. That makes window length a lever platforms can pull to look better, and a variable you must control before comparing anything.

Two rules follow. Never compare platforms on windows you have not verified are identical — a 7-day-click platform and a 30-day-click platform are not measuring the same thing. And never change a window mid-analysis without restating history, because the step change will read as performance.

• Match the window to the real decision cycle. A 30-day window on an impulse purchase mostly captures noise.
• Keep click and view windows separate, never blended into one number.
• Record the window alongside every reported figure, so a comparison is possible later.

Windows on AI surfaces

Conversational surfaces stress the concept in two directions at once.

Some outcomes are immediate and inside the window by a wide margin — an agentic conversion completes within the same session, sometimes within seconds. Others are far outside it: a user reads a recommendation, remembers the brand, and acts a fortnight later through a channel with no connection to the exposure. There was no click to start a window, and the eventual conversion looks organic.

Extending the window does not fix the second case, because the problem is a missing interaction rather than an expired one. The instrument that catches it is a holdout, not a longer lookback.