Catalina is linking with iHeartMedia to measure the sales impact of podcast advertising by packaged-goods brands—pairing the nation’s top podcast publisher with sales data covering 103 million households from 22,000 grocery and drug stores.

The deal gives a fast-growing medium solid sales impact data. It primarily covers offline sales, which still account for the majority of packaged-goods volume, but also picks up some online sales picked up at or delivered from stores that have loyalty programs Catalina tracks. But it doesn't pick up sales from Amazon, Walmart or other retailers that don't provide sales data to Catalina.

Through the partnership—which both sides said would respect privacy safeguards using anonymized data—the companies can compare purchases by people who hear podcast ads to purchases from those who don't. “We’re able to measure not only how effective it was, but how much [of the sales] were incremental” for the brand, says David Shiffman, executive VP of national research at iHeartMedia.

Podtrac ranked iHeartMedia as the top U.S. podcast publisher last month, with a unique audience of 26.9 million, almost 251 million monthly streams and 557 active shows. EMarketer predicts podcast ad revenue will grow 41% this year to $1.3 billion, topping $1 billion for the first time.

Radio and other audio advertising traditionally weren’t big for CPG advertisers, but that’s changed in recent years, particularly for Procter & Gamble Co., which was the third-largest radio advertiser last year, with spending up 10% to $130.6 million, according to Kantar. P&G Chief Brand Officer Marc Pritchard has said the increase also extends to digital as the company’s marketers found audio an effective way to reach people.

Rival Unilever also has been stepping up spending on podcasts, such as becoming a charter sponsor of Shondaland podcasts, co-produced by iHeartMedia and Shonda Rhimes, who also has worked extensively with Unilever’s Dove.

CPG advertisers have been moving to audio—be it broadcast radio or podcasts—to fill gaps in reach as traditional TV audiences dwindle and fragment, says Brian Kaminsky, chief data officer of iHeartMedia.  

The partnership with Catalina could also help more-closely link broadcast radio ads to store sales, Kaminsky says. “Using our digital platform as a collection mechanism for people who’ve been exposed to the same body of content being played out over the AM/FM tower, we’re playing that same content to select users over mobile devices,” he says, creating a panel to model sales from broadcast as well.

The Catalina relationship is, for now, about evaluating effectiveness of podcast ads, not targeting them, Kaminsky says, though iHeartMedia and Catalina have been talking about the latter for some time as well.

The Outcomes-Based Marketing approach, developed by MMA Global as a new paradigm for media planning, would fit particularly well in a system that used Catalina shopper data to target ads. MMA’s idea is to target “moveable middle” consumers, ideally using purchase histories to find people who aren’t steadfast brand loyalists or are never likely to buy a brand, no matter how many ads they’re exposed to.

While using Catalina data to find those folks in podcast audiences might be intriguing, it’s not what this partnership is initially about, Kaminsky says. And while iHeartMedia did recently open a private programmatic marketplace specifically for podcast audiences, he says the marketplace offers plenty of other ways of targeting segments based on podcast content without targeting around purchase history for now.