Nielsen delays MRC-required fixes to TV currency measurement

Nielsen is delaying two changes to its Big Data + Panel measurement framework until August, pushing back fixes the Media Rating Council (MRC) has said are necessary for the company to maintain accreditation.

Those changes could have major implications for how agencies compare historical ratings year over year, complicating ratings projections and upfront media planning. In 2025, roughly $18 billion was spent during upfront negotiations, according to EMarketer.

The MRC instructed Nielsen last September to make several changes to its Big Data + Panel currency or risk losing accreditation.

In its release, the MRC acknowledged the potential disruption: “We regret that these changes will be disruptive to business processes of the marketplace.”

The four required updates include: implementing an independent estimate of broadcast and cable viewership; modeling changes to increase demographic stability; improving demographic segments for Hispanic audiences and Spanish-language networks; and simplifying Nielsen’s weighting process.

Together, these could materially alter how historical ratings are compared, potentially rippling through forecasting, pricing and guarantees.

Nielsen was initially expected to deliver these adjustments by April, a month before most major upfront presentations. But the company emailed clients this week that two of the processes would be delayed until August.

That delay is reportedly being driven by Nielsen’s customers, who requested more time to review the revised processes and assess how much the new approach impacts reported viewership data.

George Ivie, CEO and executive director of the MRC, told The Current he didn’t know whether delays extending into August would impact the MRC’s decision to suspend Nielsen’s accreditation.

“If that’s true, it’s kind of hard for me to light them on fire if that was driven by customers, not necessarily [Nielsen’s] readiness to implement,” Ivie said.

A Nielsen spokesperson said in a statement: “We adhere to the MRC’s Voluntary Code of Conduct. Any questions about confidential MRC proceedings should be directed to the MRC itself.”

The MRC is currently receiving monthly impact data from Nielsen showing how viewership levels change under the revised methodology.

Ivie said March data will carry more weight than earlier months like January because it provides a fuller picture of how large the historical differences may be.

The trade body first became aware of Nielsen’s problems before summer 2025, after total-day impressions among adults 25 to 54 declined by more than 10% in the first half of the year compared to the same period a year before. Those declines confirm issues raised by the Video Advertising Bureau (VAB) and a major TV network about instability with Nielsen’s measurement.

Sean Cunningham, VAB president and CEO, said in a statement that the “MRC statement acknowledging significant Nielsen national data problems arrived about 10 months too late, as the damage in hundreds of millions has been done through systemic undercounting and instability.”

Cunningham added that “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 have been an MRC-delivered get-out-of-jail-free card for Nielsen."

The MRC previously suspended Nielsen’s standing with panel-only measurement back in 2021 after issues with undercounting audiences. Nielsen regained its standing for that in 2023. Nielsen’s Big Data + Panel measurement was accredited by the MRC in early 2025.