This past week, Rino Scanzoni, chief investment officer at GroupM, openly decried Nielsen’s national, sample-based TV measurement. Although Scanzoni has an inherent bias (GroupM’s parent WPP owns Nielsen competitor, Kantar, which has a set-top-box data-based TV measurement system of its own called RaPiDview), his words still speak volumes about the state of TV audience measurement and the need for a new system.

In our report earlier this year, "TV’s Currency Conversion" (client access required), we predicted that set-top-box data would start to gain traction in local markets where Nielsen’s samples were especially small and statistically unstable. Since then, data providers like Rentrak and Kantar have been gaining traction in these local markets, offering marketers granular user-level data from local cable companies’ set-top boxes. Nielsen, too, is aggregating set-top-box data as part of a push for a hybrid methodology, but these efforts are confined to its small local market; its legacy national measurement methodology continues to be based on a relatively small sample of households.

However, Nielsen has more problems on its hands than local TV measurement. Consumers are constantly multitasking with other devices while they watch TV. With attention spans no longer guaranteed during commercial breaks, marketers need new ways to measure their ads not just on TV but also across smartphones, tablets, and laptops as well. As media fragmentation continues to grow, marketers will need behavioral cross-platform metrics that measure their audiences across multiple media touchpoints.

Nielsen’s cross-platform measurement panel is certainly a step in the right direction, but we agree with Scanzoni’s own assertion that “a sample-based system doesn’t apply to the world we’re in” anymore. I believe it’s only a matter of time before a large national advertiser finds success — defined by better reach or higher ROI — with more granular metrics derived from actual viewer activity. Are you a local or national TV marketer experimenting with new TV metrics? How is your organization looking at Nielsen’s national sample of households in light of the continued media fragmentation? We’d love to hear your thoughts below or in The Forrester Community For CMO & Marketing Leadership Professionals.