• by Wayne Friedman , September 27, 2007

In four years, the Nielsen Company said, it would triple the size of its National People Meter panel to some 37,000 homes and 100,000 people, merging the sample base from its growing Local People Meter service.

Nielsen says because of media fragmentation--and other growing media platforms--it is important to add more granular data to the people meter. Nielsen has previously said it would be merging the two samples.

While the total new sample size will be 37,000 homes for NPM in 2011, Nielsen says the "effective" sample size will actually be 17,000 households, taking into account weighting of geographical distribution of the 56 local markets that have Local People Meters. Nielsen says the "effective" sample size of the NPM sample is now 10,000 homes.

Media agency researchers have been concerned about the merging of the two samples, since it adds more responsibility to those respondents.

"It's tricky," says one veteran media research executive. "You have one person contributing to two different reports. You lose some benefit of precision in looking at one person to one report. You gain more responses. But you lose the benefit of collecting those additional responses for new respondents."

The research executive said the merging of both samples was a way for Nielsen to hold down pricing costs to its clients.