Attribution Window

What an attribution window is

An attribution window defines how long after an interaction a conversion still "counts" for that interaction. If you set a 7-day click window, a purchase made six days after someone clicked your ad is credited to that ad; a purchase made eight days later is not. Windows come in two flavors — click-through (the user clicked) and view-through (the user only saw the ad) — and the choice of window length and type quietly determines how much ROAS a channel appears to earn.

Click-through vs view-through

• Click-through attribution credits a conversion to an ad the user actually clicked. It's the higher-confidence signal — clicking is an intentional act.
• View-through attribution credits a conversion to an ad the user merely saw (an impression, no click). It's far weaker evidence of causation and is the main reason platform ROAS can look inflated. A 1-day view window is much more conservative than a 7-day view window.

Rule of thumb: trust click windows, treat view-through credit with skepticism, and confirm with incrementality when a channel leans heavily on view-through.

Meta vs Google defaults (why they disagree)

The two platforms ship different defaults, so the same purchase can be credited differently in each:

• Meta: the standard setting is 7-day click + 1-day view for consented users under Aggregated Event Measurement; for unconsented iOS traffic the window narrows (1-day-click is the conservative iOS default). Meta's options and AEM constraints are documented in its attribution settings help.
• Google: defaults to a 30-day click window with data-driven attribution for most conversion actions. Google's window options are described in the Google Ads attribution documentation.

Because Google's default window is much longer than Meta's, Google has more days in which to claim a conversion — so comparing the two platforms' raw ROAS without normalizing the windows is an apples-to-oranges error.

Illustrative example

A customer sees a Meta ad, clicks a Google Search ad two days later, and buys on day five. Under Meta's 7-day click window, Meta credits the sale; under Google's 30-day click window, Google also credits it. Both dashboards show the conversion, so summing them double-counts the single purchase. This is exactly why blended ROAS — one revenue number against one spend number — is the honest cross-platform scorecard.

How to handle attribution windows well

1. Normalize before comparing channels. Set comparable click windows (or compare each platform only to its own history), never raw default-vs-default.
2. Prefer click over view. When in doubt, weight click-through credit and discount view-through.
3. Match the window to your conversion lag. Considered purchases need longer windows; impulse buys don't (see conversion-lag windows by channel).
4. Reconcile to blended MER across the same period to catch the double-counting windows create.

Common mistakes

• Comparing Meta and Google ROAS at their native defaults. Different windows make this meaningless.
• Lengthening the window to "improve" ROAS. A longer window almost always shows higher ROAS — but it's reclassifying, not creating, value.
• Forgetting view-through is in the number. A big chunk of "ROAS" can be 1-day view credit; know your split.

How Admaxxer handles attribution windows

Admaxxer lets you view conversions across consistent click windows and compare them side by side, so a longer platform default doesn't silently flatter one channel over another. By reconciling windowed platform numbers against blended MER on actual revenue, it surfaces exactly where Meta's and Google's windows are crediting the same sale — turning a confusing dashboard discrepancy into a clear, normalized comparison.