Retail Media Metrics That Actually Matter: 3 Leaders on Their Go-To KPIs

Let's be honest—we're all chasing the latest shiny metric in retail media. ROAS gets all the glory, impression share makes for great charts, and don't get me started on the alphabet soup of attribution models flooding our dashboards. But sometimes the most powerful insights come from the basics that we keep coming back to month after month.

I recently asked several brand-side leaders about that one metric that isn't necessarily sexy or new, but is absolutely essential to how they run their business. Their answers reveal something important about retail media success: the fundamentals still matter most.

When Vendor Timing Makes TACOS Essential

Luiz Antunes, National Account Manager for E-Commerce at Organika Health Products, swears by TACOS (Total Advertising Cost of Sales) despite all the complexity that comes with being a vendor on Amazon.

"One metric that I need to return again and again and it's not anything new is the TACOS," Luiz says. The challenge for vendor brands is that their revenue doesn't always align with their advertising spend timing. "We work with a budget for all the marketing spend on Amazon PPC and DSP. We have a percentage of the revenue and we are vendors on Amazon. So our revenue comes from Amazon orders that depend on logistics, et cetera."

This timing mismatch becomes especially pronounced during events like Prime Day. "When you have an event, like for example Prime Day, orders come before our spend came later. So if you look at this percentage, it won't work," Luiz says. His team has developed a calculation that checks the difference between Amazon POS, Amazon revenue, and their shipments to get a clearer view of budget tracking.

"We look at the TACOS because it brings a clear view of how we are tracking regarding our budget," he says. While his team is exploring other metrics like new-to-brand and repeat purchase rates, TACOS remains mandatory for daily tracking.

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Market Share: The North Star in Competitive Categories

Danny Silverman, Growth Consultant at Silver Stream Strategic Consulting, returns to one of the original KPIs that has guided his entire career: market share.

"I've been diving deep back into market share lately, and it's, for me, one of the original KPIs going all the way back through my entire career," Danny says. "The reason why I love market share is especially right now with so much churn and change in the categories—whether or not you're winning or losing, it's not just about whether your sales are growing or profitability, but how you're doing relative to competition."

For Danny, market share serves as an absolute anchor in a rapidly changing landscape. "Market share is one of those KPIs I think is just an absolute anchor. But in our space, often gets neglected because of whether it's cost or accuracy concerns around accuracy, whatever it might be. But I think it's an important one to have in your stable of KPIs."

New-to-Brand: The Ultimate Discovery Metric

Elizabeth Rivas, E-Commerce Marketplace Director at AlgaCal, focuses on metrics around new-to-brand performance, viewing them as the foundation of her marketplace strategy.

"One metric I keep coming back to, and that really guides our strategy, is all metrics around new-to-brand. So obviously it's not that flashy like ROAS, but for us it's really everything," Elizabeth says. "Because our mindset at AlgaCal is all about brand discovery and when it comes to marketplaces, that is really the goal of that channel."

Elizabeth's approach goes beyond just tracking new customer acquisition. "So it's about how do we get people to know the brand, get to know us, trust us, and choose us for their bone health solution. So rather than focusing on ROAS or ACOS, when I work with my ad agency, we actually track month over month growth in new-to-brand customers."

Her team digs deeper using Amazon's tools and AMC (Amazon Marketing Cloud) to understand which formats drive the best new customer acquisition. "We now are looking into new-to-brand performance, but by ad type. So which formats are actually bringing in new customers? Like is it Sponsored Products, Sponsored Brands? If it's brands, is it static, like product collections, or is it video, or is it upper mid-funnel DSP?"

This granular approach helps them understand what types of creatives resonate most with first-time shoppers and guides their campaign planning strategy.

The Bottom Line

What stands out across these insights is that the most reliable metrics aren't always the most glamorous ones. While the industry chases new attribution models and sophisticated measurement frameworks, these successful practitioners ground their strategies in fundamentals that directly connect to their business goals.

Whether it's TACOS for budget management, market share for competitive context, or new-to-brand for discovery, these metrics prove that sometimes the best insights come from mastering the basics rather than chasing the latest trend.

Hear more about favorite metrics from past other retail media leaders here: Which new metrics these 3 retail media leaders are embracing