NPR has the equivalent of a podcast testing lab that's now starting to reap huge financial dividends. For instance, the media organization late last year wanted to launch a new politics podcast, so it pitted a week-in-review concept versus a controversial/shocking programming idea on NPR One, its streaming news and podcast app. Results trickled in, akin to a classic A/B split test, and a podcast called NPR Politics was born.

"The shocking one beat the other idea hands-down, so we went that route," explained Gina Garrubbo, president and CEO of National Public Media (NPM).

The testing methodology, said Bryan Moffett, NPM's general manager, "is our little secret sauce to get the content to the point where its ready to launch."

That anecdote underscores how NPR has evolved to become a radio-podcasting dynamo, taking successful radio shows and repackaging them for digital listeners. It also plucks the best podcasts and synthesizes them for broadcast patrons. The upshot? Podcasting is driving sales that are 10 times greater than two years ago; they were up 70 percent in 2016 compared to the prior year. NPM's fiscal year ended on Sept. 30.

While NPM didn't reveal raw revenue figures, radio accounts for 70 percent of sales with the rest (30 percent) coming from podcasting. Next year, the media organization, which is best known for Morning Edition and All Things Considered, forecasts 35 percent of its sales will come from podcasting.

"The Renaissance/revolution of spoken-word audio is where it starts," Garrubbo remarked. "It's a new format. We are able to incubate shows and send them out as podcasts."

NPR's podcasts like PlanetMoney, How I Built This and Code Switch are often attracting digitally-minded marketers for brands such as Squarespace, Emma and StitchFix who then get schooled on traditional-media reach.

"They come in through the I-want-to-buy-podcasting-door-because-I-think-it's-cool door," said Garrubbo. "They end up spending more money in radio because they realize that—even though podcasting reaches their demo and even though it's effective—it's a smaller audience. And they realize the unparalleled size and loyalty in broadcast is still there. We have some clients that buy digital exclusively and radio exclusively, but more and more they are buying across platforms."

The reason brands are drawn to her podcasting-radio offering seems to come to life in other data, chiefly that 70 percent of listeners, according to its surveys, hold more positive opinions of companies that support NPR.

NPR's self-described "muted" messaging style for ads is also important, Garrubbo attested.

"It's not a hit-you-over-the-head message," she said.