Add-to-Cart is a Vanity Metric. Here's What Brands Should Measure Instead

Retail media ad spend in the U.S. is forecast to hit $71.09 billion in 2026, according to EMARKETER. Yet despite the innovation happening in the channel to capitalize on that buzz, one thing that hasn’t evolved is measurement. The worst offender? Add-to-cart rate.

On the surface it’s easy to see why it’s popular. When we’re looking to prove campaigns work, it’s a tangible number to include in reports. However, high add-to-cart numbers are nothing more than a vanity metric if they don’t translate to sales.

False Signals

From a pure function point of view, add-to-cart is no different from a click to a product page. It might signal interest, but it tells you nothing about whether that shopper completed checkout, abandoned the basket, or was already planning to buy before your ad appeared. As a proxy for sales performance, it’s about as reliable as a landing page visit.

And yet it carries disproportionate weight in campaign reporting because it feels commercial. It looks closer to a transaction than an impression and feels easy to defend internally.

Look closer, though, and it gets murkier. Different retailers define add-to-cart differently. Some count guest checkouts; others require login and some log attempted cart actions regardless of outcome. The industry is increasingly comparing campaigns and vendors against a metric that isn't standardized.

We've been here before with clickthrough rates. Despite being denounced long ago for being ineffective, somehow they still end up in RFPs today.

Legacy Logic

Retail media inherited this habit from the early e-commerce boom, when brands became fixated on the promise of DTC-style attribution — the idea that you could finally connect an ad directly to a purchase. Add-to-cart sat closer to the transaction than impressions or clicks, so the industry began treating it as shorthand for commercial intent. Once it got embedded in reporting decks and RFPs, it took on a life of its own.

What gets measured gets managed. And what gets managed becomes very hard to remove, even when it stops being useful.

The problem is sharper now because the stakes are higher. Consumers are more price-sensitive, willing to trade down to private label, and less loyal to brands. In that environment, the real value of retail media is not generating cart activity from people who were already going to buy. It’s reaching customers who wouldn't otherwise have converted — new-to-brand shoppers, lapsed buyers, households that have drifted toward competitors.

Meaningful Metrics

That is the conversation retail media should be prioritizing, and incrementality is the metric that makes it possible. Not "did someone click?" but "did this campaign drive behavior that would not have happened anyway?" Incremental return on ad spend, new-to-brand reporting, and household penetration data can answer that question.

Despite the tools existing, we need to ask ourselves why the industry seems so intent on defaulting to familiar metrics and whose job it is to move the industry forward. Is it industry bodies, agencies pushing back on clients or should this come from the brand level to demand better measurement?

Ultimately if we want to see real growth, we need to stop just accepting the numbers and push back on what they really mean. Retail media will not mature into a credible performance channel while it optimizes toward metrics that measure activity instead of outcomes.

Add-to-cart can stay in the deck but when it comes to sales, let’s not pretend it’s anything other than a vanity metric.

Yuni Baker-Saito is the CEO and co-founder of Chicory, the leading contextual commerce advertising platform for CPG and grocery.