NASCAR’s Big Data ratings problem isn’t going away

Nielsen’s methodology changes are again resulting in lower NASCAR audience estimates as the racing circuit returns to linear television. That is despite the fact that these changes have generally boosted viewership for other live sports.

The NASCAR Cup Series race from Sonoma, the first of five to air on TNT Sports, averaged 1.9 million viewers according to data from Sports Media Watch.

But that number was recorded through Nielsen’s older panel standard. In September 2025, Nielsen shifted to Big Data + Panel, which adds additional viewership data from smart TVs and set-top boxes. Nielsen says the new methodology results in a more accurate audience estimate. As a bonus, it has generally boosted live sports viewership, sometimes by up to 15%.

But not for NASCAR. The Sonoma race averaged a slightly lower 1.8 million viewers, according to Big Data.

That was also the case for earlier NASCAR races on FS1, leading NASCAR to criticize the new standard and officially announce that it would report only panel viewership as its official numbers.

However, NASCAR’s five-race slate on Prime Video didn’t suffer from this problem. As with most live sports, average viewership was 15% higher when measured by Big Data (2.3 million) than through panel (2.0 million), according to SMW.

When NASCAR’s Big Data viewership problems were occurring across the board, it was easy for the racing circuit to point the blame at Nielsen. However, the fact that the issue only exists on linear television poses a much more difficult problem for NASCAR.

NASCAR is heavily reliant on cable television for its races, especially under its most recent media rights contract, which saw a 40% increase in media rights fees but also resulted in more races moving from over-the-air television to cable.

This comes as cord-cutting continues, and those who remain on cable skew older. A July 2025 MNTN research study found that 73% of Baby Boomers watch two or more hours of TV daily, compared to just 36% of Gen Z.

Whatever the cause, this is a problem that NASCAR needs to get to the bottom of. NASCAR can’t simply sit back while other sports leagues use Big Data to announce record-breaking ratings.

For the moment, NASCAR seems to think the answer might be additional changes to Nielsen’s methodology. Brian Herbst, NASCAR’s EVP and chief media and revenue officer, told Sports Business Journal in May, “We are in active conversations with Nielsen on future methodology changes, particularly what’s rolling out end of August, beginning of September, with impact data, which we think will more accurately reflect kind of the audience measurement of our sport.”