Achieving an effective frequency – more specifically, the coveted “frequency of three” – is a time-honored tenet in the world of advertising. In that spirit, our Audience Insights series addresses the topic of Nielsen measurement and methodology for a third consecutive month. For this edition, we’ll focus on three components of the well-publicized challenges with 2021 TV viewership estimates.

1. In a surprising reversal, Nielsen concedes TV viewership has been underreported.

For much of this year, Nielsen had responded to mounting pressure around potential disparities in its 2021 TV ratings and impressions data by channeling the spirit of Lt. Frank Drebin of Police Squad fame – i.e., “nothing to see here…please disperse.” That has changed in recent weeks, though, as the Media Rating Council (MRC), the independent organization responsible for auditing and accrediting audience measurement services, concluded that Nielsen has, in fact, been undercounting and underreporting television viewing, largely due to pandemic-influenced challenges related to maintaining the panel of “Nielsen homes” that form the backbone of Nielsen’s TV measurement service.

2. Industry experts contend Nielsen’s acknowledgment tells only part of the story.

The VAB, a prominent television advocacy group that has been a leading voice in calling for more transparency around Nielsen’s numbers, wants the investigative work to continue. “Both Nielsen’s analysis and the MRC statement essentially contradicts months of Nielsen’s denials on any significant problem,” VAB President and CEO Sean Cunningham said in a statement. “What we saw was, to say the least, the tip of the iceberg.” Much of that assertion stems from VAB findings that showed a year-over-year decline of approximately 20% in Nielsen’s average number of in-tab homes, which are the homes that provide usable data for calculating viewership estimates. As noted in our previous post on this topic, that’s the TV measurement equivalent of a basketball team having to play an entire game with only four players.

3. Local measurement challenges can be compounded by “vanishing viewers” in key demos.

Unlike household-level reporting, persons-based viewing estimates for key age ranges such as 18-49 and 25-54 are based on non-passive measurement and indirect modeling, including Nielsen’s viewer assignment methodology. Cox Media analysis suggests that, even at the national level, the year-over-year changes are far more pronounced for persons-based estimates. In first quarter 2021, for example, Nielsen reports year-over-year viewership declines of more than 20% for ad-supported cable and 23% for broadcast among adults 18-49 – compared to declines of 8% and 13%, respectively at the household level.   Additional Cox Media analysis determined that Nielsen’s local population estimates for the 18-49 and 25-54 age ranges have declined at a disproportionately high rate within the traditional TV universe. These anomalies in Nielsen’s population estimates can create a “vanishing viewer” effect for local markets that already are reliant on smaller Nielsen samples, ultimately exacerbating measurement challenges whenever persons-based demographics are used as the foundation for evaluating local TV campaigns.

Like a good late-night infomercial, this TV measurement saga is likely to have more “but wait…there’s more” moments as new data are released and analyzed. To that end, Cox Media teams are actively analyzing local data and are available to provide more information or address campaign-specific questions. Stay tuned to the Cox Media Blog for more Audience Insights!