U-shaped attribution
Updated 2026-11-02
Definition
U-shaped attribution, also called position-based attribution, gives the most credit to the first and last visits. The first gets 40%, the last gets 40%, and the remaining 20% is split evenly across the visits in between.
The logic is that two moments matter most: the one that introduced the buyer and the one that closed the sale. The middle still counts, just less. The credit, charted by visit, makes a U.
Example
This example uses made-up numbers. A buyer pays $2,000 after five visits.
| Visit | Channel | Share | Credit |
|---|---|---|---|
| 1 | Organic search | 40% | $800 |
| 2 | 6.67% | $133.33 | |
| 3 | Referral | 6.67% | $133.33 |
| 4 | 6.67% | $133.34 | |
| 5 | Paid search | 40% | $800 |
With only two visits, there is no middle, so each gets 50%. With one visit, it gets 100%.
Strengths and limits
U-shaped is a sensible middle ground. It rewards both demand creation and demand capture, without ignoring the steps between. The weights are a convention, though. Nothing in your data proves that 40/40/20 is the right split for your business. Treat it as a useful view and compare it with others.
How Headstream measures it
Headstream uses exactly these weights: 40/40/20, and 50/50 when there are two visits. Use the u_shaped model in the API, or select it in the revenue report. Every session in your lookback window counts as a touchpoint, and the amounts are rounded so the credits add up to the payment exactly.
Refunds and disputes credit back to the original sale using the same split. Attribution relies on Stripe, and connecting Stripe is in beta. See revenue attribution for how the models work together.