Attribution
Conversion window
Also called click window.
Conversion window is how long after a touch a conversion may still be credited to it. It is set per click or per view.
How it is measured
The system compares the timestamp of the touch with the timestamp of the conversion and counts it if the gap is within the window. Windows are often given as 7, 30, or 90 days and may differ by touch type.
Read the setting in your ad platform and your analytics tool. Different defaults explain many gaps between their conversion counts.
Worked example
A mattress retailer's average time from first click to order is 16 days. The ad platform uses a 7-day window and credits 120 conversions for the month. The analytics tool uses 30 days and credits 214.
The 94 extra are real orders that came after day 7. The retailer picks 30 days as its standard and notes that the ad platform report undercounts. Its cost per acquisition drops from $88 to $49 for the same spend.
How it differs
A conversion window limits how long a touch can earn credit. A lookback window is the span the model scans back for touches. They are often set together and confused.
Common errors
Leaving defaults in place. Using one window for products with different buying cycles. Comparing platforms with different windows. Changing the window after seeing results. Forgetting view-through windows.
In practice
Measure the typical time from first touch to purchase for your business. Set the window to cover most buyers. Use the same setting in every tool you compare.