Definition
Position-based attribution assigns most credit to the first and last touchpoints, with the remaining credit spread across the middle touches.
Example
A 40/40/20 model gives 40% to first touch, 40% to last touch, and 20% to the middle steps.
How to use it
- Use when you believe first touch creates demand and last touch captures it.
- Be explicit about the rule (for example 40/40/20) to keep comparisons stable.
- Validate with lift tests when budget decisions are material.
Common mistakes
- Changing the split across reports and breaking trend comparisons.
- Using it as a causal truth without incrementality checks.
Measured as
Measure Position-based Attribution (U-shaped) with a fixed attribution window, conversion event, and spend basis before comparing campaigns or creative tests.
Misused when
- Changing the split across reports and breaking trend comparisons.
- Using it as a causal truth without incrementality checks.
Operator takeaway
- Use when you believe first touch creates demand and last touch captures it.
- Be explicit about the rule (for example 40/40/20) to keep comparisons stable.
- Validate with lift tests when budget decisions are material.
- Use Position-based Attribution (U-shaped) only inside a stable attribution rule, conversion definition, and time window so campaign comparisons stay honest.
- If performance changes, check whether the metric moved for a real business reason or because the measurement setup changed underneath you.
Next decision
- Read Attribution vs incrementality: what to trust, when, and how to test if the decision depends on interpretation, policy, or trade-offs beyond the raw formula.
- Decide which report owns Position-based Attribution (U-shaped) before comparing campaigns, channels, or creative tests.
Where to use this on MetricKit
Guides
- Attribution vs incrementality: what to trust, when, and how to test: A practical guide to attribution vs incrementality: common attribution models, window pitfalls, how MER/marginal ROAS fit in, and how to run holdout/geo tests.