In what likely is the biggest methodological change in the way it measures national TV viewers since it introduced people meters in 1987, Nielsen Wednesday began informing clients of a new twist in its sample expansion plan that will effectively utilize mathematical modeling to estimate viewing for about half of its sample.
While an email sent to clients Thursday implied that details of the plan were “previously discussed,” some clients were surprised -- and befuddled -- by what they said was the new twist, which Nielsen described as an enhancement of its “viewer assignment methodology.”
According to clients, and confirmed by a Nielsen spokesperson, that enhancement will essentially use mathematical modeling to double the size of its persons viewing and demographic estimates. Nielsen will do this by attributing data from its actual national people meter sample to its household tuning data generated by TV “set meters” in its local TV markets.
“Nielsen will apply a demographic assignment methodology informed by [national people meter] viewing behavior to report persons level ratings,” the spokesperson explained, adding: “We've been working on this with the industry for nearly two years.”
Nielsen said the new methods would begin contributing to its national TV ratings estimates effective Sept. 29 -- just after the start of the new season -- and that it would release data on the impact of those methodological changes to a client committee and to industry watchdog the Media Rating Council in the first quarter of 2015.
It was not clear at presstime whether the MRC has approved the changes, and whether they will impact its accreditation of Nielsen’s national TV ratings service, but it appears that these changes will be ongoing for some time as Nielsen integrates different elements of its sample expansion plan, which also includes the addition of some actual people meter households in its sample.
Nielsen’s national people meter sample currently is about 25,000 households, and Nielsen said it will add 2,200, but did not say when that expansion would be completed. It also said the addition of those homes, and the implementation of its new methodology would double the “effective sample size” of its national ratings panel, which implies nearly half of the effect will be coming from mathematical modeling.
One long-time Nielsen customer described Nielsen’s statement that it will double the effective sample size of its national TV ratings as misleading, because some customers may infer that it will reduce Nielsen’s sample error by half. But he said that would require Nielsen to quadruple the size of its sample, not double it.
Nielsen said it was making the changes to “address concerns over fragmentation in the television landscape by increasing ratings stability.” Another likely motive is that it will enable Nielsen to take on new customers whose audience might have been too small to be measured with statistical accuracy with via its smaller sample.
In a separate announcement made Wednesday, Nielsen also announced details of a local TV ratings sample expansion.“As previously communicated in May, Nielsen plans to increase the sample in five Local People Meter (LPM) markets over the next several months,” the Nielsen spokesperson said, adding: “The five markets are Dallas, Denver, Houston, Miami and Washington DC. These LPM sample expansions will leverage the new Scrolling Text People Meter, which is the latest Nielsen Global Television Metering hardware platform. The first wave of replicates will begin to contribute to these local markets' samples with the data of September 29, reported on September 30. We plan to provide dates for the remaining replicates at a later point in time.”
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