U-shaped Attribution

U-shaped attribution is the common configuration of the position-based model that gives 40% of credit to the first touch, 40% to the last, and the remaining 20% to the middle touches.

U-shaped attribution takes its name from the shape of the weight distribution: the two ends high and the middle low, just like the letter U. It is a subset of the position-based family and operationalizes the same assumption: initial discovery and final closing are the two decisive events of the journey and should take the most credit. The 40-20-40 split is conventional but not sacred; some organizations shift the ratios, which shows U-shaped is a choice, not a truth. Where the model slips is journeys with only one or two touchpoints: with a single touch all the credit goes to it and the model collapses into single-click, and if a middle nurturing stage played a real and large role, the fixed 20% under-counts it.