Time-to-conversion distribution
The time-to-conversion distribution is the spread of elapsed times between an early interaction and the eventual conversion across a population. Reading it reveals how much of your conversion volume is fast versus slow, which is essential for choosing lookback windows, interpreting recent-period reports, and avoiding the mistake of judging campaigns before slow conversions land.
What this means
Some conversions happen minutes after the first interaction; others take days or weeks. Plotting the elapsed time from first (or last) touch to conversion across many conversions gives the time-to-conversion distribution — typically right-skewed, with many quick conversions and a long tail of slow ones.
This shape tells you how patient your measurement must be. A business with a long tail cannot judge a campaign in its first days, because much of its eventual conversion volume has not yet arrived.
Why it drives window choices
Lookback and reporting windows should be informed by the distribution, not guessed. If conversions routinely take three weeks, a seven-day window discards real credit; if nearly all convert within a day, a 90-day window mostly adds noise and stale paths.
The distribution also explains conversion lag in recent reports: the latest days always look weak because their slow conversions are still pending. Google documents conversion-lag and path-length reports that expose this. The practical move is to read recent periods as provisional and let the tail mature before drawing conclusions.
- Usually right-skewed: many fast, a long tail of slow
- Informs sensible lookback and reporting windows
- Explains why recent periods always under-report
How it appears in analytics and logs
A long tail in time-to-conversion means recent periods under-report; conversions for those interactions have not happened yet, not that the campaign failed.
Diagnostic use case
Inspect the time-to-conversion distribution to set lookback and reporting windows that capture slow conversions and to avoid under-counting recent campaigns.
What WebmasterID can help detect
WebmasterID's first-party timestamps on path touches and conversions let you build a time-to-conversion view without third-party identifiers.
Common mistakes
- Judging a campaign before its slow conversions have landed.
- Picking a lookback window without checking the distribution.
- Reading the freshest days as final rather than provisional.
Privacy and accuracy notes
The distribution aggregates elapsed-time data across users, not individual identities. This page is educational, not legal advice.
Related pages
- Conversion lag (time-to-conversion)
Conversion lag is the time between an interaction and the resulting conversion. Some conversions happen minutes after a click; others take days or weeks. Because of lag, recent activity always looks under-performing at first — conversions for recent touches have not happened yet — and the lookback window must be long enough to capture them. It is a core reason attribution reports change as data matures.
- Lookback and conversion windows explained
A lookback (or conversion) window is the period before a conversion in which earlier touchpoints are eligible for credit. Touches outside the window are ignored entirely. Because every attribution model only sees touches inside this window, its length quietly governs which channels can ever receive credit.
- Decay half-life in time-decay attribution
In time-decay attribution, credit declines exponentially the further a touchpoint is from the conversion, and the half-life is the parameter that sets how fast. A touch one half-life before the conversion gets half the credit of one at conversion time; two half-lives back, a quarter. Choosing the half-life decides how strongly recency is rewarded — a model choice, not a measured fact.
- Event Explorer
Inspect timestamps between touches and conversions.
Sources and verification notes
- Google Ads Help — About conversion lag and time lag reportsDocuments time-lag/path-length reporting for time-to-conversion analysis.
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.