Position-based (U-shaped) attribution
Position-based (U-shaped) attribution gives most credit to the first and last touchpoints — commonly 40% each — and shares the remaining 20% among middle touches. It tries to honour both discovery and closing while still acknowledging the middle. The specific weights are a convention, not a measured truth.
What this means
Position-based attribution splits credit by where a touch sits in the path. A common preset gives 40% to the first touch, 40% to the last, and divides the remaining 20% evenly among the middle touches. It is a deliberate compromise between first-click, last-click, and linear.
The weights are a convention
Nothing measures that openers and closers deserve exactly 40% each — it is a reasonable-sounding default. Different tools expose different weights, and changing them changes the story. The model also rewards being in the first or last slot, which depends on the lookback window and on whether the true endpoints were tracked.
It is a sensible narrative model, but the numbers should be read as assumptions you can edit, not as channel contribution.
- Heavy credit to first and last touches
- Remaining credit shared across the middle
- Weights are configurable conventions, not measurements
How it appears in analytics and logs
Position-based output is shaped by the weights you chose. A channel that tends to open or close paths is structurally favoured; pure middle-of-path channels are structurally muted.
Diagnostic use case
Use position-based when you believe the opening and closing touches matter most, while treating the 40/20/40 weights as an editable assumption rather than a finding.
What WebmasterID can help detect
WebmasterID keeps weighting schemes explicit and confidence-labelled, so a U-shaped view is read as one configurable lens rather than as ground truth.
Common mistakes
- Treating 40/20/40 as a derived rather than chosen split.
- Comparing U-shaped reports with different weight settings.
- Forgetting endpoint credit depends on the lookback window.
Privacy and accuracy notes
Position-based attribution needs only the order of one site's own touchpoints. No cross-site identity is required to apply the U-shaped weights.
Related pages
- Linear attribution: equal credit to every touch
Linear attribution divides a conversion's credit equally among all touchpoints in the path. It is the simplest multi-touch model: every touch matters the same. That even-handedness avoids the single-touch extremes, but it also pretends a fleeting impression and a decisive demo are worth the same — which is rarely true.
- Time-decay attribution: recent touches weigh more
Time-decay attribution weights touchpoints by recency: the closer a touch is to the conversion, the more credit it earns, usually following an exponential decay with a configurable half-life. It is a compromise between last-click and linear, but its recency bias under-credits the early demand-creating touches.
- First-click attribution: crediting the opener
First-click attribution assigns 100% of a conversion's credit to the very first touchpoint a visitor had. It is the mirror image of last-click: it celebrates discovery and awareness channels while ignoring everything that nurtured and closed the journey. Useful for studying acquisition, misleading as a sole budget lens.
- Attribution analytics
Configurable weighting, clearly labelled.
Sources and verification notes
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.