The way national TV audiences are measured in the U.S. is entering a new era. Effective September 1, 2025, Nielsen will fully transition to its Big Data + Panel methodology as the sole dataset for national TV transactions—marking the official retirement of Panel-Only ratings for currency purposes.
This change follows the Media Rating Council’s accreditation of the Big Data + Panel methodology and re-accreditation of Nielsen’s traditional panel, creating a hybrid system that blends the scale of big data with the demographic accuracy of people-based panels, and should allow for greater understanding of media buys across devices.
Key Dates Ahead
September 1, 2025: Big Data + Panel becomes Nielsen’s single endorsed dataset for all national TV transactions. All Nielsen rankings, program lists, and network averages transition to this methodology.
January 1, 2026: Panel-Only Automatic Content Measurement (ACM) is removed from transactional systems, though it will remain available for certain analytics and historical comparisons.
What Clients Should Know
- The data behind your buys is changing
Big Data + Panel combines return-path and smart TV data from 45M+ households and 75M devices with Nielsen’s opt-in, audited panel. This enables deeper audience granularity and broader coverage across devices and platforms. - Your historical trends may shift
Because Big Data + Panel blends multiple data sources and calibrates for biases, some program or network ratings may differ from what you’ve seen under Panel-Only. This can affect pacing, reach, and cost-efficiency metrics. - Nielsen rankings and competitive reporting will look different
Nielsen’s weekly Top 200 and Top 250 lists for broadcast, cable, and total programming will all be based on the new dataset, potentially affecting competitive benchmarks. - Some analytics will still use Panel-Only for historical periods
While transactions will shift to Big Data + Panel, Panel-Only will remain for prior years and some long-term trend reporting—so be aware of mixed methodologies in longitudinal analysis.
Questions to Ask Your Agency Partners
- Methodology impact
How will the transition to Big Data + Panel affect my current buys, performance projections, and ROI calculations? - Historical comparisons
How will you ensure fair comparisons between historical Panel-Only data and the new Big Data + Panel ratings? - Optimization opportunities
Will Big Data + Panel allow for more precise audience targeting or daypart optimizations in our upcoming campaigns? - Competitive analysis
How will changes in program and network rankings impact our competitive positioning and share of voice? - Verification and transparency
How is the agency reconciling its own numbers and projections against Nielsen’s updated dataset?
Bottom Line
By September 1, 2025, Big Data + Panel will be the industry’s single measurement currency for national TV. By January 1, 2026, Panel-Only ratings will disappear from transactional systems.
Clients should be proactive now—reviewing historical baselines, talking with agencies about potential shifts, and understanding how the new dataset could influence planning and performance measurement. This is not just a technical upgrade; it’s a fundamental shift in how the industry measures audiences, and it will shape buying and evaluation strategies for years to come.