references/theories/commerce-media-incrementality.md

# Commerce Media Incrementality

## Theory

Use this as an applied decision model, not as proof that the model is correct in every market.

## Use when

- When retailer or marketplace media reports closed-loop ROAS.

## Mechanism

Measure incremental business impact with counterfactual methods and account for retailer/customer overlap, substitution, margin, and baseline purchase probability.

## Applied marketing use

Route the diagnosis to the specialist agents and skills connected in `neural/graph.json`; verify current platform facts using `references/2026/commerce-media-2026.md`.

## Failure modes

- Treating a current platform feature as a permanent law of marketing.
- Selecting the theory because it sounds modern rather than because it explains the observed constraint.

## Related principle

- `causal-rigor-over-platform-attribution`

## Sources

- `source:iab-commerce-media-2026`
- `source:iab-commerce-incrementality-2025`