A campaign promotes a new Greek yogurt. The post-campaign report shows two numbers:
Same-SKU ROAS: 3.2x
Halo ROAS (including basket companions): 6.8x
Same campaign. Same data. Two very different stories about what the investment was worth.
What each metric tells you
Same-SKU ROAS measures the return generated by the specific product that was promoted. Sales of that SKU among exposed shoppers vs. the control group, divided by the campaign investment. It's the narrow view, did the promoted product sell more?
Halo ROAS includes the same-SKU impact plus the incremental sales of related products in the exposed shoppers' baskets. Products that weren't promoted but benefited from the campaign's influence on shopping behavior.
Same-SKU ROAS tells the brand story: "Our product sold more." Halo ROAS tells the business story: "The campaign grew the basket."
Why you need both
Reporting only same-SKU ROAS understates the campaign's value. The promoted yogurt drove sales, but the exposed shoppers also bought more granola, more berries, and more almond milk. That basket growth has real value, to the brand's portfolio and to the retailer's category.
Reporting only halo ROAS risks overclaiming. The halo effect might include products that were already trending up, or products where the causal link to the campaign is weak. Halo needs to be measured rigorously, through control group comparison, not assumption.
The honest approach: report both. Show the brand what their specific product achieved (same-SKU). Show the full business impact including basket companions (halo). Let the brand and the retailer see the complete picture.
The portfolio implication
For multi-brand companies, halo ROAS is often the more important number. A campaign promoting Brand A might lift Brand B (a sibling brand) through basket association. The total portfolio return exceeds the individual brand return.
This changes how portfolio brands should evaluate retail media. The investment isn't in one brand, it's in a basket position. The ROI calculation should include portfolio effects, not just the promoted SKU.
The retailer's perspective
Retailers care about category growth, not just brand performance. Halo ROAS demonstrates that the campaign grew the total basket, which is the retailer's interest.
A campaign with modest same-SKU ROAS but strong halo ROAS is a category growth story. "The campaign drove €80,000 in incremental basket sales beyond the promoted product" is a compelling message in a category review.
The bottom line
Same-SKU is the narrow win. Halo shows the real basket impact. Both are valid. Both should be measured through control groups. And both should appear in the post- campaign report.
The brand that sees only same-SKU ROAS undervalues the campaign. The brand that sees both understands the full investment case. And the RMN that provides both builds credibility and earns the right to price for the total value delivered.
Related Reading
- Incrementality: The Metric That Turns Retail Media Into a Growth Budget
- Rate Card Architecture: The Difference Between a Price and a System
- Halo Sales: The Lift Retail Media Hides Outside the Promoted SKU
- Likelihood to See: When Retail Media Moves From Conditions to Evidence
- Carrefour Retail Media Network: FMCG Advertising in Romania
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