Post-impression vs post-click
Post-click attribution credits a conversion to an ad the user clicked; post-impression (view-through) attribution credits a conversion to an ad the user saw but did not click, within a window. Post-click rests on a deliberate action; post-impression rests on an ad being served and (sometimes) viewable. They measure different strengths of evidence, and mixing them without labels inflates totals.
Two different kinds of evidence
A post-click conversion requires the user to have clicked the ad and later converted within the click window. The click is a deliberate signal of interest.
A post-impression conversion only requires that the ad was served (often with a viewability standard) and the user later converted within the view window, with no click. The evidence is exposure, not action — much weaker, and far easier to over-credit.
Why the distinction matters
Because impressions vastly outnumber clicks, post-impression windows can sweep up conversions that would have happened anyway, inflating reported performance. Post-click is more conservative but can undercount genuine awareness effects of display and video.
Good practice keeps the two counts labeled and separate, and uses incrementality testing to decide how much view-through credit is real rather than coincidental.
- Post-click: user clicked, then converted in the click window
- Post-impression: user only saw the ad, then converted
- Never merge the two into one total without labels
How it appears in analytics and logs
A campaign whose conversions are mostly post-impression is being credited for exposure, not action — weaker evidence that warrants an incrementality check.
Diagnostic use case
Separate clicked conversions from viewed-only conversions so display and video are not judged by the same yardstick as search clicks.
What WebmasterID can help detect
WebmasterID records observed on-site conversions independent of impression pixels, giving a click-and-action baseline to compare against view-through claims.
Common mistakes
- Summing post-click and post-impression into one inflated total.
- Judging display by the same standard as search clicks.
- Trusting view-through credit without an incrementality test.
Privacy and accuracy notes
Post-impression credit depends on impression and viewability signals, which are increasingly limited by privacy controls. Educational, not legal advice.
Related pages
- View-through conversions: credit for impressions
A view-through conversion credits an impression a user was served but did not click, when they later convert within an impression window. It tries to value awareness that does not get clicked, but it is among the easiest credits to over-count, because seeing is not the same as being influenced.
- Incrementality testing: what attribution cannot tell you
Incrementality testing measures the lift a channel actually causes by withholding it from a control group and comparing outcomes. It answers the question every attribution model dodges: would this conversion have happened anyway? It is causal where attribution is merely correlational, but it requires deliberate experiment design.
- Incremental vs total conversions
Total (attributed) conversions are every conversion a channel gets credit for under some model. Incremental conversions are the subset that would not have occurred without that channel — the causal effect measured by a holdout. The difference matters because a channel can be credited with conversions it merely rode along on. Total answers 'how many did we attribute here?'; incremental answers 'how many did this channel actually cause?'
- Attribution analytics
Compare action-based conversions to view-through claims.
Sources and verification notes
- Google Ads Help — View-through conversionsDefines view-through (post-impression) vs clicked conversions.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.