# Lina's Channel ROMI — Chapter 3 Worked Example | The Defensible Decision > The five-channel marketing-attribution dataset behind Lina's clustered-column failure vs the single-encoding Big Idea rebuild in Chapter 3 of The Defensible Decision. Five channels, four metrics each, one audience question — and one chart shape that answers it in three seconds. Canonical URL: https://www.thedefensibledecision.com/datasets/lina-channel-romi/ [Teaching Datasets](/datasets/) / Lina's Channel ROMI — Chapter 3 Worked Example The five-channel marketing-attribution dataset behind Lina's clustered-column failure vs the single-encoding Big Idea rebuild in Chapter 3 of The Defensible Decision. Five channels, four metrics each, one audience question — and one chart shape that answers it in three seconds. ### Files Markdown files open in the browser. Data files download directly. [Markdown README.md 3.6 KB](/datasets/lina-channel-romi/README.md) [Markdown SCHEMA.md 1.5 KB](/datasets/lina-channel-romi/SCHEMA.md) [CSV lina-channel-romi.csv 183 B](/datasets/lina-channel-romi/lina-channel-romi.csv) [JSON lina-channel-romi.json 2.2 KB](/datasets/lina-channel-romi/lina-channel-romi.json) Start with [README.md](/datasets/lina-channel-romi/README.md) for purpose and limitations, then use [SCHEMA.md](/datasets/lina-channel-romi/SCHEMA.md) for field definitions.