Business-news network CNBC is planning to stop using Nielsen ratings as the basis for the sale of advertising on its daytime schedule to advertisers, The Wall Street Journal reported Tuesday morning, in a maneuver that calls into question one of the bedrock elements of the TV business at a time when big chunks of audience are consuming video in non-traditional ways.

CNBC is planning to use data from a marketing research firm called Cogent Reports to provide advertisers with data that will help them determine the price of ad time on the cable network. the Journal reported. CNBC executives have long said the size of the network’s audience is not measured accurately by traditional Nielsen measures, since much of its viewership comes from people who are at work in offices or other places, not the living room of their homes.

Even so, CNBC’s daytime ratings have sagged in recent months. According to the Journal, the network wooed an average of audience of just 177,000 people in 2014 between the hours of 9:30 a.m. and 5 p.m., down 17% from the average it secured in 2004 and 13% from what it lured in 2013. Those hours would not include one of CNBC’s most popular shows “Squawk Box.”

NBCUniversal isn’t the first big media company to question Nielsen’s effectiveness in recent weeks. Viacom Chief Executive Philippe Dauman recently told investors his company’s networks, which include youth-skewing outlets like MTV and Comedy Central, would press to devise new products that did not rely on Nielsen measures as a base. Among the ideas are new distribution methods that would make the company’s programming available on-demand to various mobile devices.

“For networks with niche audiences like CNBC, pure age and gender-based ratings are not always the best means against which to sell,” a Nielsen spokeswoman told The Journal, which reported that CNBC rival Fox Business Network intended to maintain its use of Nielsen measurement. Another business-news network owned by Bloomberg LP has never used Nielsen.

Nielsen in November reported that it had successfully determined for the first time that out-of-home viewing lifted viewership of some daytime programming, part of a test, but that appears to be too little to sway the people who run CNBC.

The Journal reported that CNBC will start using Cogent ratings in the fourth quarter of 2015. The company will survey over 1,000 investors and financial advisers on their media habits during the day and use that data to provide ratings for CNBC.