Position-Based Attribution

Position-based attribution rewards the bookends of the journey. In the common 40-20-40 form, the first touchpoint gets 40% of the credit, the last gets 40%, and the remaining 20% is split among everything in between. It's sometimes called U-shaped attribution, because the credit dips in the middle and rises at both ends.

Why it matters

This model encodes a specific belief: the channel that first found a customer and the channel that finally closed them are the two that matter most, and the nurturing touches in the middle matter less. For many businesses that's a reasonable instinct — it values discovery and closing equally while still acknowledging the middle did something.

A concrete example

A path runs organic search, then email, then a referral, then direct. Position-based attribution in GA4 gives organic search 40%, direct 40%, and splits the remaining 20% between email and referral — 10% each. Compare that to last-click, where direct would have swallowed the whole conversion and organic search would have shown nothing.

The common misreading

The model bakes in an assumption that the middle touchpoints are minor, which isn't always true — sometimes a mid-journey email is what actually convinced someone. Reading position-based numbers as objective influence overstates the ends and understates the middle. Treat the 40-20-40 split as a chosen viewpoint, not a measurement of real contribution.