A top executive of NBC, which has been struggling with diminishing ratings, said viewers are being undercounted as television viewing increasingly shifts to DVR playback, the New York Post reports.

Ted Harbert, chairman of NBC Broadcasting, urged the television industry to adopt a new ratings system that accounts for the shift, the story reports. Harbert made his comments during the network’s upfront presentation to advertisers Monday in New York.

The story reports: "Advertisers currently pay for airtime based on viewers who play back a show within three days of its initial broadcast. The metric is called ‘C3’ — ‘C’ for commercials, because it measures how many people watch the ads as opposed to the show itself, and ‘3’ for the three-day window.”

Harbert urged advertising executives to start paying for playback for as long as seven days after the show’s initial broadcast.

With NBC ranked last among the big four broadcast networks, the tweak would give the network a boost, the story notes.