Nielsen Media Research has agreed to provide the broadcast networks with a new stream of data showing the average ratings for the national commercials within a program.

The networks requested the data several weeks ago and the data they get will be based on live viewing plus delayed viewing for seven days on digital video recorders.

Speaking at a meeting of the Advertising Research Foundation in New York on Tuesday, David Poltrack, executive VP and chief research officer for CBS, said he expected the data-along with the current streams of program ratings-at the beginning of the 2006-07 season. But the new data would not be used during the current upfront or as currency until the 2007-08 season.

Jack Loftus, senior VP of communications for Nielsen, said the average commercial ratings data will be made available to the networks in the live-plus-seven format, but it will be also made available in the other formats-live or live plus same day-if that’s what other clients want.

Mr. Loftus said that “no one has canvassed the ad agencies yet,” and that no one has asked the cable networks what they want.

Advertisers and media buyers have been seeking increasing measures of how well their investments in TV advertising work, and the call for commercial ratings is part of that effort.

But during his presentation, Mr. Poltrack said, “We question your sincerity,” and said calls for accountability might in fact be a negotiating ploy.

“It worked this year,” he said, noting that advertisers will be paying nothing for viewers who watch commercials while playing back shows on their digital video recorders. “Consider that a bonus from us to you,” he said.

Mr. Poltrack downplayed the impact commercial ratings would have because past studies have shown that despite changes in technology, the rate of commercials avoidance has remained steady over the years.