View-through conversion
A view-through conversion is credited when a user sees an ad without clicking it, then converts within the attribution window.
What does View-through conversion actually mean?
A view-through conversion (VTC) is attributed when a user sees an ad without clicking it and then converts within a defined window (usually 1-7 days). Meta's default is 1-day view; YouTube uses 30-day view; Display campaigns historically used 30-day view.
View-through attribution is the most controversial type. The mechanism is real (seeing an ad can trigger eventual conversion without a click), but the magnitude is wildly inflated by platforms because long view-through windows capture conversions that would have happened anyway. A 7-day-view + 28-day-click window can credit up to 30% more conversions than reality.
Most mature performance teams either disable view-through attribution entirely or scrutinize VTC-heavy campaigns through holdout testing. Display and YouTube remarketing are the usual offenders. They show ads to in-market audiences who would have converted regardless, then claim credit for those conversions.
Example
A user sees a YouTube TrueView ad without clicking. Three days later, they search the brand on Google and buy. With 30-day view-through enabled, YouTube claims credit. A holdout test would likely show this user would have converted anyway.
When it matters
View-through inflates platform-reported ROAS, especially on Display and YouTube. Run holdout tests on VTC-heavy campaigns to find the truth.
Related terms
Last-click attribution
Last-click attribution credits the final ad click before conversion with 100% of credit. The default model on most ad platforms; systematically over-credits bottom-funnel.
Attribution
Attribution determines which ad touchpoint receives credit for a conversion, using last-click, first-click, time-decay or data-driven models.
Incrementality
Incrementality measures the additional revenue ads generate vs. what would have happened without them, usually measured via holdout tests or geo-experiments.
Holdout test
A holdout test withholds ads from a randomly-selected control group, then compares performance vs. the test group to measure incremental lift.
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