Want to be a Nielsen family? You’ll soon have a better chance

NEW YORK — The company that measures TV viewership announced a significant expansion Wednesday, saying it would triple the number of “Nielsen families” over the next four years to keep better track of new ways of watching television.

Nielsen Media Research said it wants 37,000 homes, with 100,000 people, reporting on its viewing habits by 2011. That’s about triple the current sample size of 12,000 households with 35,000 people.

“The larger you make it, the more stable the data, the more precise the data,” said Sara Erichson, executive vice president for client services at Nielsen North America, “and that’s a very important thing for the industry, which uses this information for currency.”

For years, Nielsen has attached a “people meter” to the TV sets of participating families. But now, measuring viewership also means keeping track of who is watching on computers, cell phones, iPods and sets in public places.

Clients are also demanding more precise data, such as demographic details for small cable networks or by-the-minute ratings of who is watching commercials.

The sample sizes now are so small for some of the niche cable networks that if only one regular viewer happens to go on vacation, it could significantly affect the ratings, said Alan Wurtzel, chief researcher at NBC Universal.

“Sample expansion is always good,” he said.

The change will also mean the retirement of Nielsen’s written diaries. To get precise ratings for a local market, Nielsen has long had a separate sample that required participants to remember what they watched and fill out diaries.

By 2011, Nielsen will use “people meters” for its local samples in 56 media markets. Currently, this is being done in 10 big cities, with Seattle, Houston and Tampa being added this fall.