CPM is easy to compare. That's its strength and its curse.
When a brand's media team evaluates retail media alongside programmatic display, social, and DOOH, CPM is the common denominator. €15 CPM for in-store screens. €8 CPM for programmatic. €6 CPM for social. The comparison is instant, and retail media loses every time.
But the comparison is wrong. Because CPM measures the cost of an impression, not the cost of an outcome. And retail media's value is in the outcome.
The CPM trap
CPM compares channels on the cheapest common metric: cost per thousand opportunities to see. It treats all impressions as equal, a banner served to a bot on a low-quality website and a screen viewed by an identified shopper about to make a purchase decision.
When retail media is priced and evaluated on CPM, it always looks expensive relative to channels that optimize for cheap reach. Programmatic display can deliver impressions at €2-3 CPM. In-store screens are €12-20 CPM. The math seems obvious: digital is 5-10x more efficient.
Except it's not. Because the programmatic impression can't prove it drove a sale. The in- store screen can, through the closed loop, the identified shopper, the purchase attribution, the control group.
The CPM comparison penalizes retail media for the very thing that makes it valuable:
the data and measurement infrastructure that connects impressions to sales.
Outcome metrics protect value
The alternative is to price against outcome metrics, metrics that reflect the actual business value delivered.
Cost per incremental sale. The campaign investment divided by the number of incremental sales (as measured by control groups). This normalizes the comparison: how much does it cost to generate one additional sale through this channel?
Cost per new-to-brand buyer. The campaign investment divided by the number of new-to-brand acquisitions. This measures the cost of growing the customer base, a metric every brand cares about.
Incremental ROAS (iROAS). The incremental sales value divided by the campaign investment. This is the return on investment metric, how many euros of incremental sales for every euro invested.
Cost per share point. The investment required to move market share by one point.
This connects to the strategic metrics that drive brand and category planning.
Each of these metrics is harder to compare across channels, because most channels can't calculate them. That's the point. Outcome metrics differentiate retail media from channels that can only report delivery.
Why harder to compare is better
If your metric is easy to benchmark, you're competing on price. If your metric is hard to benchmark, you're competing on value.
CPM is easy to benchmark. Every channel has a CPM. Procurement tools compare them automatically. The conversation defaults to "who's cheapest?"
Cost per incremental sale is hard to benchmark. Most channels can't measure incremental sales. There's no procurement tool that compares it. The conversation defaults to "who delivers the most value?"
Retail media wins the second conversation. It loses the first. The choice of value metric determines which conversation you're in.
The transition
Moving from CPM pricing to outcome pricing requires:
1. Measurement capability. You can't price against outcomes you can't measure.
Incrementality measurement, control groups, and closed-loop attribution must be in place.
2. Confidence. You need historical data showing consistent outcome delivery. "We consistently deliver 4-6x iROAS across breakfast category campaigns" is a pricing anchor.
3. Education. Brands and agencies need to understand why outcome metrics matter and why CPM comparison is misleading. This is a sales conversation, not a technology conversation.
4. Packaging. Outcome-based packages that include measurement make the value metric natural. When the product is "50,000 new-to-brand buyers with 5x iROAS," the pricing conversation is about the outcome, not the impression.
The bottom line
CPM is easy to compare, which is why it destroys value for premium channels like retail media. Outcome metrics are harder to compare, which is exactly why they protect value.
Price against what retail media delivers: incremental sales, new-to-brand buyers, measurable ROAS. Not against what every other channel also delivers: impressions.
The metric you price against determines the conversation you're in. Choose the one where retail media wins.
Related Reading
- Same-SKU ROAS vs Halo ROAS: Two Retail Media Stories, One Truth
- 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
Ready to see how this works in practice?
Footprints AI helps brands and retailers measure what matters. See our customer success stories or get in touch to discuss your retail media strategy.
