The C3 commercial ratings used to buy and sell advertising fell 13% among adults 18 to 49, according to an analysis of Nielsen data by Wall Street analyst Michael Nathanson of MoffettNathanson Research.

Cable ratings were down 11% and broadcast was down 16%, Nathanson said.

TV ratings got a boost in 2016 when Nielsen switched to a bigger sample size.

“Ratings declines in 2017 were even worse than we imagined, with seven of the past 11 months declining double digits,” Nathanson said in a report.

Nielsen and the networks do not release C3 figures.

21st Century Fox’s networks were the biggest decliners among cable channels. A+E Networks and Disney were the only cable network owners to post gains in primetime among 18-to-49 year-olds.

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Among individual cable networks in total-day C3 ratings, Nathanson said A&E was up a whopping 40% for the month. Also posting gains were Hallmark Channel, up 12%; History, up 9%; MSNBC, up 8%; and Freeform, up 7%. Viacom’s MTV was flat.

The biggest decliner was Fox News Channel, followed by Viacom’s Nick at Nite. It's worth noting that Fox News uses live-plus-same-day ratings as it primary ad sales metric. The network recently noted that it has had its highest rated year in its history on a total-day basis.

The declines by the broadcast networks came against the backdrop of the presidential election a year ago, which brought viewers to their sets. Fox, which had a huge World Series finale a year ago, was the biggest decliner.

”Given the challenged ratings trends we have seen and expect to continue, we remain cautious on the TV advertising market’s ability to grow dollars by offsetting these declines with higher CPM inflation,” Nathanson said.

A+E Networks said it will offer to guarantee that its data-based campaigns will reach specific target audiences, rather than a number of viewers in the traditional broad demographic categories during the upcoming ad market.

The company launched its A+E Precision platform last year and tested it with a handful of clients. Those clients have returned, launching more campaigns using Precision and spending more money.

A+E is also extending the Precision platform to include Viceland, the network A+E owns with Vice Media, and will use the platform to buy audiences for multiplatform campaigns across linear, digital VOD and over-the-top.

TV companies have been diving into data as a way to compete with digital outlets that promise more targeted and accountable advertising. Lately, advertisers have been having doubts about those promises and so ad dollars have been swinging back to TV.

Data enables networks to identify shows that have viewers that fit a marketer’s target consumer and sell those specific audiences, rather than broader audiences measured by Nielsen’s C3 and C7 commercial ratings, which have been falling across the industry.

Santosh Mathai, vice president of analytics & strategic sales partnerships at A+E Networks, said that in the early days, clients still wanted to fall back on guarantees based on Nielsen demographic ratings. Now, they’re more open to transacting on audiences. “If an audience guarantee is something that you’re looking for, we’re open to doing business with you,” he said.

A+E Precision is one of the ways the programmer will offer to work more closely with clients during its upfront presentation and negotiations. During the upfront auctions, cable networks sell more than half of their commercial inventory.

“We’re invested in this space in terms of being able to deliver against audiences, which clients are looking to do,” Mathai said. Precision campaigns have access to inventory on all of A+E Networks. “The schedule is determined by audience discovery,” Mathai said.

“The purpose here is to find the audience and find the audience where you wouldn’t have otherwise seen them,” Jason DeMarco, vice president of programmatic and audience solutions at A+E, added. “If you’re looking to target the soccer mom that might be in the market for a minivan, traditionally you’re not going to air on the History channel. But this will tell you, ‘This actually pops’ at this particular time.”

Mathai said A+E’s initial tests were with clients that also wanted to learn about the space and know their target audiences, in categories including entertainment and financial services. In the early phases, clients achieved “tremendous efficiencies” in lowering the cost of reaching their target. “When you look at those numbers, the improvement is in the double digits.”

A+E has also started working with programmatic partners, such as TubeMogul and clypd to sell audience to clients working with buy-side platforms.

Programmatic deals are reviewed before they are finalized, and A+E is setting prices at levels it believes are appropriate based on audience discovery, Mathai said.