How each model works
Last-click
All credit to the final touch. Simple, and systematically over-credits bottom-funnel channels.
Multi-touch
Spreads credit across touches by a fixed rule (linear, time-decay, position-based) you did not derive from data.
Causal
Estimates the counterfactual and credits only incremental conversions.
Where each misleads
Last-click buries everything that created demand. Multi-touch feels fairer but the weights are arbitrary and still describe correlation, not causation. Causal attribution is the only one that answers "would this sale have happened anyway?" - but it requires modeling and honest uncertainty.
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Side-by-side
| Last-click | Multi-touch | Causal | |
|---|---|---|---|
| Question answered | Who was last? | How to split credit? | What was caused? |
| Basis | Rule | Rule | Counterfactual model |
| Handles overcounting | No | No | Yes |
| Output | Credit | Credit | Incremental ROAS + interval |
Frequently asked questions
Is multi-touch better than last-click?
+
Marginally - it spreads credit, but the weights are still arbitrary and non-causal.
When should I use causal attribution?
+
For budget decisions, where you need caused sales, not credited sales.
