The media industry’s go-to authority for measuring audiences acknowledged on Friday that the recent coronavirus pandemic bent its yardstick, but maintained nothing is broken.

Nielsen, under fire from the TV networks that depend on it to count the audiences for which advertisers pay, says pandemic conditions resulted in a smaller panel of consumers it relies on to monitor TV viewing, but believes the trends it chronicles during 2020 remain viable. “What we have seen is that the decline in linear is definitely increasing,” Mainak Mazumdar, Nielsen’s chief data and research officer, says in an interview. “There is an increase in streaming, but the decline in linear is not offset by total viewing.”

The TV companies believe Nielsen allowed its measurement process — the bedrock of deals struck with advertisers — to deteriorate between March of 2020 and March of 2021, leading to a significant undercounting of the audience. They say Nielsen didn’t dispatch field agents to monitor the technology it has in individuals contracted to report viewing to Nielsen and did not replace panelists as they relocated around the nation during the pandemic. That resulted in notable shortfalls in tracking audience viewing. Nielsen is releasing Friday, but it offers “a four-ounce solution to a 10-pound problem,” says Sean Cunningham, CEO of the VAB, a trade organization that represents TV networks to Madison Avenue.

“During the COVID-19 period, Nielsen transformed the way it manages its panel to leverage more remote techniques and address the challenges of this unprecedented time,” Nielsen said in a release meant to address the networks’ concerns. “While this drove a sample size smaller than it was pre-COVID, it remains robust and representative.”

Citing its data, Nielsen says spikes in TV viewership that began during the early days of the pandemic eventually settled down — and suggests the effects of the coronavirus on TV production crimped the flow of the original content that would have kept viewers better engaged. “In aggregate, the combination of more repeats, delayed premieres, programs produced in homes (and basements) and the lack of sports heightened the challenges for the TV industry — challenges that inspired some audiences to seek out new content. SVOD programming, news and nostalgic comedy programs fared well, but the overarching shifts in total TV viewing are bigger than specific program genres,” Nielsen said Friday.

Looking at October, Nielsen said its data shows that the networks aired 13% fewer new episodes, compared with the same month a year earlier, leading to a 75% increase in programming repeats. The company has also noticed explosive growth for ad-free streaming outlets like Netflix and Disney Plus, as well as a 39% increase in streaming audio consumption between May 2020 and January 2021 — even without people using commutes to work to listen to podcasts.

Speaking Thursday, the VAB’s Cunningham suggested that Nielsen’s research does little to address the destabilization of the marketplace its changes in process have created and likened it to putting a Band-Aid on a gaping flesh wound. The white paper, he said, “falls way short” of what advertisers need to understand a period of measurement the TV industry believes represents an “anomaly.”

The issue comes to a boil as the nation’s big media companies prepare for the industry’s annual “upfront” market, when U.S. TV networks try to sell the bulk of their advertising inventory ahead of their next cycle of programming. Nielsen ratings are the bedrock of how TV networks and media agencies set prices, and many advertisers build out placement of their clients’ commercials by “mirroring” audience levels from the prior year.

This isn’t the first skirmish between the networks and Nielsen in recent months. In July of last year, Nielsen reversed a last-minute decision to not implement a new measure of so-called “out of home” viewing — audiences watching TV in offices, bars, hotels and the like — even though the networks had sought it. Nielsen cited the pandemic’s effects on viewership in those venues as a reason to delay launch of the new system. The networks, which had already established ad deals with the new measurement involved, went ballistic, and even demanded a public apology. Media outlets and advertisers have increasingly found themselves at odds as new technology forces changes in the systems both sides have relied upon for decades.