What is Attribution Window?

Why It Matters

The attribution window setting can make a campaign's reported ROAS swing sharply overnight without anything about the campaign or actual sales changing at all, which makes it one of the most consequential, and most overlooked, configuration choices in performance reporting. Comparing performance across campaigns or platforms only makes sense when they're using the same window, since a longer window will always look like it's crediting more conversions than a shorter one for identical underlying behavior. Understanding a product's typical purchase timeline is also what should drive the window choice, since a window too short for a long consideration cycle will systematically undercount real campaign impact. Ignoring this setting means performance comparisons across time or across campaigns can be comparing apples to oranges without anyone realizing it.

Example

A campaign using a 7-day click attribution window credits itself with a sale that happens 5 days after someone clicked the ad, but the same sale would go uncredited under a 1-day window. Switching a campaign's reporting from a 28-day to a 7-day attribution window can make ROAS appear to drop sharply overnight, even though nothing about the campaign or the underlying sales actually changed, which is why comparing performance across campaigns only makes sense when they use the same attribution window.

Frequently Asked Questions

• What's the difference between a click window and a view window?

  A click attribution window credits conversions that happen after someone clicks an ad, while a view window credits conversions after someone simply saw an ad without clicking it. View windows are typically shorter than click windows on most platforms.

• What attribution window length is standard?

  Common defaults are 1-day, 7-day, and 28-day windows, and the right choice depends on how long a typical customer takes to decide and purchase after first seeing an ad for that specific product.

• Why does changing the attribution window change ROAS?

  A longer window captures more conversions that happen further after the ad interaction, which increases the conversions credited to the same spend, so ROAS rises with a longer window and falls with a shorter one for identical underlying sales.

• Can you compare campaigns using different attribution windows?

  Not reliably. Comparing performance across campaigns or platforms only produces a fair comparison when they're using the same attribution window, since window length alone changes reported results.

• How do you choose the right attribution window?

  Matching the window to the actual customer decision timeline for the specific product, longer for considered purchases and shorter for impulse buys, gives a more accurate read than defaulting to whatever the platform sets automatically.