Audience measurement company Nielsen said on Wednesday that it’s finally able to track how many people are watching Netflix shows like Stranger Things and The Crown, as well as licensed content streaming on Netflix, potentially unlocking a key data set that has thus far eluded the rest of Hollywood. Netflix, however, remains unconvinced.
Nielsen, the company whose name is synonymous with network and cable TV ratings, has been trying for a few years to expand its measurement capabilities to cover the rapidly-growing streaming entertainment market. Meanwhile, Netflix (along with other big streaming players) is very protective of its viewership data, which the streaming service claims is made irrelevant by the fact that Netflix does not rely on ad sales like its traditional TV rivals.
Today, Nielsen announced a new service, called Subscription Video on Demand (SVOD) Content Ratings, which will show its media subscribers just how many people are watching the thousands of titles streaming on Netflix, including the streaming service’s growing list of original programming. And, much as it does with traditional TV networks, Nielsen will also offer audience and household demographic data that aims to break down Netflix audiences based on age, gender, etc.
“The significant growth of SVOD services in entertainment markets across the world has created demand from rights owners to understand the size and composition of audiences relative to other programs and platforms,” Megan Clarken, the president of Nielsen’s media measurement unit, Watch, said in a statement. “The syndication of SVOD measurement as part of Nielsen’s Total Audience offerings represents a big step forward in terms of moving closer to transparency within the SVOD marketplace.”
Get Data Sheet, Fortune’s technology newsletter.
So far, the new Nielsen service will only track Netflix viewership, though Nielsen expects to add Amazon Prime and Hulu data sometime in 2018. Eight TV networks and movie studios have already signed on to the new service, Nielsen said on Wednesday, including A&E Networks, Walt Disney’s ABC, Lionsgate, Comcast’s NBCUniversal, and Time Warner’s Warner Bros.
Netflix likes to stay coy about exactly how it leverages its user data when deciding which programming to green-light. And, the refusal of many streaming companies to release viewer statistics has been a source of ongoing debate in the entertainment industry, which helps explain why Nielsen is so eager to offer Hollywood a more comprehensive look at audience activity as more and more viewers flock to streaming entertainment.
Netflix is making no secret of its skepticism when it comes to Nielsen’s latest attempt to capture its audience data. “The data that Nielsen is reporting is not accurate, not even close, and does not reflect the viewing of these shows on Netflix,” a Netflix spokesperson said in a statement.
Aside from the lack of public support from Netflix, Nielsen’s new service could also suffer from the fact that it does not yet measure how many people watch Netflix programming on mobile devices, which likely represents a large chunk of viewership. According to ComScore, Americans watched 7.5 billion minutes of Netflix content on their smartphones in June 2017 alone.
UPDATE: A Nielsen spokesperson sent Fortune a statement responding to Netflix’s response to the new Nielsen service. “We continue to collaborate with our clients on new measurement solutions and feel confident in the data produced by our proprietary technology and service that measures Subscription-based Video On Demand (SVOD) content. These independent insights will help them understand their content lifecycle and finally shine a light on what was, to this point, an industry blind spot,” Nielsen said.
