For top network programs, the data reveals that "commercial ratings" are practically the same when shows are viewed "live" as when they are viewed via DVRs ("live plus seven day"), meaning that people are making good use of the fast-forward functions during the ads.

While the data is not actually ratings for specific commericals, it provides the average audience for each minute--including minutes with ads in them--and is being used as a proxy for commerical ratings.

In February, commercial ratings for CBS's "CSI" and NBC's "ER" in the adult 25-to-54 demo were the same for "live" viewing as they were for the "live plus seven day" metric--while Fox's "American Idol" Tuesday edition and ABC's "Desperate Housewives" showed that less than 1 percent of viewers using DVRs watched the ads.

For example, CBS's "CSI" posted an 8.1 rating during commercial breaks when viewers watched the show "live"--the same rating as when viewers watched with DVRs. NBC's "ER" had the same result, delivering a 6.7 during commercials in "live" numbers and a 6.7 in "live plus seven day."

"American Idol" posted a 12.1 in "live" numbers during commercials and a 12.2 in "live plus seven day," meaning that less than 1 percent of DVR viewers stopped for the ads. The same tiny increase goes for "Desperate Housewives," which saw a 10.2 during commercial breaks in "live" viewing and a 10.3 in DVR viewing.

Ad-skipping and its effect on the industry is sure to provoke conversation at the AAAAs Management Conference for Agency CEOs this week in Arizona.

The analysis combines two new forms of Nielsen data that debuted last fall: DVR ratings and minute-by-minute ratings. The DVR ratings provide a "live" category (viewership during the broadcast airing) and a "live plus seven day" number, which provides a breakdown of how many people viewed a program with a DVR in the seven days after broadcast.

The minute-by-minute data--which is new in the sense that Nielsen now offers it in a more user-friendly form--allows a determination of how many people stayed tuned during a commercial break.

By overlaying the two data streams, advertisers can get a sense of how many DVR users are watching their commercials.

While DVR ratings are widely available, minute-by-minute ratings have stayed largely under wraps. Only The Weather Channel on the selling side--and Starcom MediaVest and ZenithOptimedia groups on the buying side--are known to have purchased the data from Nielsen. Nielsen has made the DVR data available to the media, but in a sign of how much of a hot-button issue the commercial ratings are, has declined to release that information to the press.

The four shows--"CSI," "ER," "American Idol" on Tuesday, and "Desperate Housewives"--are the leading shows on each of the Big Four networks in the adult 25-to-54 demo. While advertisers in general prefer the adult 18-to-49 demo, many marketers target adults 25 to 54, and a sizable portion of upfront business is conducted based on the demo.

The data's unavoidable conclusion--that DVR users are aggressive ad skippers--is hardly ground-breaking stuff. Research showing that huge percentages of DVR users fast-forward through commercials has been around for years, but Nielsen's new minute-by-minute ratings provide more concrete evidence.

How--or if--to attach a value to ads skipped via DVRs promises to be one of the more hotly contested issues as buyers and sellers square off in the coming upfront. Networks have argued that ads viewed in fast-forward mode still have some value, since they provide at least some exposure. Buyers are expected to resist, arguing against paying for ads that are intentionally avoided.

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