NEW YORK (CNNMoney.com) -- Nielsen Media Research, the firm that calculates national television ratings for shows, will start providing a reading on how many people are watching the commercials starting this November, according to a report published Tuesday.

The Wall Street Journal reports that executives at both TV networks and advertisers expect the new Nielsen ratings will show that viewership declines noticeably when a program breaks for commercials. The paper reports the ratings could accelerate the flow of advertising dollars out of television to the Internet and new digital media.

"Prices should go down," media buyer Bruce Goerlich told the paper. "If I was a buyer, I would be taking the stance of, 'Quite frankly, what you said you were delivering, you weren't.'" Goerlich is an executive vice president at ZenithOptimedia, the ad buying service owned by Publicis Groupe (Charts).

But television executives told the newspaper they don't expect the television ad prices to fall due to the new ratings.

"The bottom line is that there is still no better way to reach a mass audience," Jeff Zucker, CEO of NBC Universal Television Group, told the newspaper. NBC Universal is a unit of General Electric (Charts).

The newspaper reports the new ratings will measure the average viewership for all the national commercial minutes that run during a program, although they won't track individual commercials or specific commercial time slots.

Nielsen will use set-top monitors already in 10,000 U.S. homes, checking viewers' televisions several times per minute to determine what show is on. The monitors can tell whether viewers are changing the channel during a commercial break or zapping through the break with a digital video recorder, such as TiVo.

Nielsen viewers are supposed to use another device to record when they leave a room in which a set is playing, according to the report. A Nielsen spokesman told the newspaper the company believes more than 90 percent of its viewers comply with this rule.

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