- John Consoli, Mediaweek

NEW YORK DVR impact on broadcast ratings is significant and growing, according to data released by media agency buying unit Magna Global USA. Magna's research shows that less than one-fourth of all U.S. TV households have DVRs, but they account for 9 percent of the major networks' TV ratings and 15 percent of viewing by adults 18-49.

Steve Sternberg, evp of audience analysis for Magna, said DVR households "use them with a vengeance." He added the impact of DVR viewing on ratings is twice as high as the impact of VCRs when they were in 90 percent of TV homes.

Magna projects that by 2012, DVR penetration will increase to 37 percent of TV homes. At that point, nearly 25 percent of all prime-time viewing on the broadcast networks among adults 18-49 is forecast to be time-shifted.

The Magna study shows that there is little correlation between rating size of a show and its percentage of DVR playback. But it also indicates a clear link between the program genre and the amount of time-shifted viewing.

Regardless of audience size, action and sci-fi dramas all have above-average DVR playback. Leading the way are NBC's Heroes and ABC's Lost.

The study also showed that although more women watch prime-time shows, there is "very little difference" in the amount of DVR viewing done by women and men.