Nielsen has decided to postpone the launch of the meters in Chicaog and Los Angeles till June due to sampling problems, while it says it is ready to go ahead with the project of replacing the manually maintained 'sweeps diaries' in NY City on 8 April.

The Nielsen notice to broadcasters on the same drew stringent opposition from News Corp, which said on Monday that there is "growing evidence" that the use of people meters to measure local audiences "could undercount viewership by as much as 25 percent," especially among young people and minority groups, and said that the problem was particularly pronounced in large, ethnically diverse urban areas."

Detailed ratings data on a daily basis would be available from the nation's biggest city from 8 April, but Lachlan Murdoch, News Corp's deputy COO and chairman of the Fox Television Stations Group says he "cannot understand how Nielsen can still proceed with the meter in New York while such significant issues remain as to the reliability of their numbers." Murdoch, in his statement has been categorical that "If the meter isn't good enough for Los Angeles and Chicago yet, it certainly isn't good enough for the nation's largest market."

While Nielsen has used people meters since 1987 to track daily national TV viewing habits, it has deployed them only in 50 markets, limited to overall household ratings. Detailed demographic information available for local TV stations to set advertising rates thus far comes from manual diaries recorded four times a year for the "sweeps" -- in November, February, May and July, but these have been open to criticism of inaccuracy owing to viewers' tendencies to fill them in at the end of the period.

Nielsen, a unit of Dutch publisher VNU has maintained that the meters, are far more accurate than the diaries. Its only reason for delaying the launch of meters in LA and Chicago is the time taken to develop accurate samples. Nielsen spokesman Jack Loftus says "In New York, we were very confident in the quality of the sample, so we went ahead with it as scheduled." He disputes News Corp's contention that the electronic system undercounts viewership, saying, "We told them just the opposite was true."

While reports indicate that News Corp's apprehension in subscribing to the meters could stem from lower ratings garnered electronically from these cities for Fox stations than when recorded in the diaries, Murdoch in his statement argues that the meters methodology may be "flawed - particularly in large, ethnically diverse urban areas - we recommended conducting a review prior to roll out."

Nielsen began the use of local people meters in Boston in 2002, with plans to expand the system to four more cities -- Los Angeles, New York, Chicago and San Francisco -- this year, and the remaining top ten markets by 2006.

"Until Nielsen can prove the accuracy of its numbers, particularly in counting young and African-American viewers, we risk implementing a seriously flawed system. Nielsen has an obligation to design a system that inspires real confidence among broadcasters, advertisers and viewers. It must take all necessary steps, including an independent audit of the people meter methodology, to ensure that this new measurement system is credible and reliable before deploying the system in any markets," says Murdoch in his official statement.