Heading into upfronts, the accreditation of a major TV measurement product remains in limbo

The accreditation status of Nielsen’s Big Data + Panel offering remains up in the air—and it’s set to stay that way for some time longer.

The Media Rating Council (MRC), a third-party organization that accredits media research and ratings products, has not yet made a decision about the accreditation status of Nielsen’s Big Data + Panel since first kicking off a review last fall. The MRC first began evaluating the measurement product in September, and Nielsen was asked to address several concerns raised about the accuracy of the figures it was providing in the product. Those concerns included more accurately representing demographic segments and adjusting its weighting to reduce errors, Marketing Brew reported in the fall.

Since then, the offering’s accreditation status has remained in limbo, and there have been delays to the MRC’s decision to give Nielsen more time or begin the process of stripping accreditation. The organization held a meeting in February, where a decision about whether Nielsen’s product would be accredited was once again pushed, according to two sources familiar with the goings-on of MRC member meetings.

Last week, the MRC provided a public update noting that while Nielsen has proposed solutions and made “notable progress” in addressing some of the concerns, MRC members were still waiting to obtain impact data from Nielsen to evaluate the effects of changes to its modeling and weighting processes.

Because the impact data is being rolled out in phases, MRC’s review remains incomplete, and it will take even longer before a final evaluation can be reached, the MRC said.

“We understand and we regret that these changes will be disruptive to business processes of the marketplace; we are encouraged that Nielsen is actively working to address the priority areas for improvement that have arisen in their Big Data + Panel measurement,” a letter from the organization read. “We will continue to evaluate the estimated impacts of these planned methodological changes, with urgency, as they are important to Nielsen’s current accreditation of the commerce significant National service, which continues to be under evaluation at this time.”

According to the MRC, Nielsen plans to implement adjustments to its modeling and weighting processes by April. This year, upfront week will be held in mid-May, although negotiations and plans are often inked ahead of that.

“Should the expected timing be modified or delayed,” the organization added, “MRC will determine next steps on how to proceed.”

Bill Daddi, who serves as a spokesperson for the MRC, said in an email that Nielsen’s national service remains in review. Elaine Wong, Nielsen spokesperson, declined to comment about the MRC meeting or about the updated timeframe, noting that “any questions about confidential MRC proceedings should be directed to the MRC itself.”

Some in the industry are less than pleased about the delays surrounding the decision. Sean Cunningham, president and CEO of the Video Advertising Bureau (VAB), a trade group representing TV networks, told us that the update from the MRC “arrived about 10 months too late.”

“Every problem called out in the statement was already on parade by May 2025,” Cunningham, who is a vocal critic of Nielsen over the years, wrote in an emailed statement to Marketing Brew. “To have an industry watchdog process that can somehow extend into March 2026 as Nielsen rushes long-overdue ‘fixes’ to their long-denied data defects benefits only Nielsen. In my opinion, this statement and its associated dragged-out process has been an MRC-delivered get-out-of-jail-free card for Nielsen.”

The nitty gritty: Big Data + Panel first received accreditation in January 2025 accreditation, and Nielsen has looked to improve the product to keep it in good standing. In a letter sent to clients in late January, the measurement company noted that it would enhance its Big Data + Panel and its Household Demographic Assignment Model (HDAM), which Nielsen said “aims to correct existing model limitations” and will provide better representation of the tuning-in levels of younger and older homes.

Nielsen has also begun incorporating data from the MRC-accredited Advertising Research Foundation’s DASH TV Universe Study, which details how consumers watch TV across platforms and devices. In January, Nielsen told Variety in response to the study’s addition that it “ is committed to producing the most accurate and relevant data possible for our clients,” adding that “this enhancement, in coordination with many of our recent product innovations, helps us do that.”

The measurement firm is also leaning into new initiatives, including a co-viewing pilot program where panelists wear measurement gadgets that pick up audio and gauge shared viewing. The product was first tested at last month’s Super Bowl and will continue to roll out throughout the first half of the year.

Everyone’s a critic: Because Nielsen’s numbers are widely used to negotiate advertising rates, inaccuracies could have major revenue implications for TV companies, and the VAB, whose member companies include Disney and NBCUniversal, has served as a loud critic of Nielsen. In December, the VAB dropped a report detailing its additional concerns with Nielsen’s Big Data + Panel product. The report, which analyzed data from 33 networks from Sept. 15 to Oct. 12, claimed that there was more than wide audience variances on Big Data + Panel and Panel-Only measurement in certain buying demographics, and that 1 in 10 hours overall saw “severe variances” between Big Data + Panel and Panel-Only for the key 18-34 year-old demographic.

At the time, Nielsen issued a statement saying that the VAB report “is seriously flawed and manipulated,” and charging that “the VAB is wasting the time and money of its members.”