• by Wayne Friedman , September 25, 2009

The first four big days of the broadcast season might tell you of something that the networks have not seen in recent years -- very little broadcast erosion.

The collective average ratings of the big five broadcast networks was at a Nielsen 15.4 rating among 18-49 viewers, down just 3% from a 15.8 a year ago. Total shares for the five networks were 42 versus 41 through the first four days a year ago.

Broadcast television might have been up much more if not for its biggest loser, NBC -- off almost a full rating point to a 2.5/6 from a 3.4/8 a year ago. ABC is down slightly to a 4.0/10 from a 4.3/11 a year ago. CW is also down a bit among 18-49 viewers to a 1.1/3 from a 1.5/4 a year ago.

The silver lining is that ABC -- with its big Wednesday and Thursday wins -- is the No. 1 network so far among 18-49 viewers. Big winners versus last year's results so far are Fox and CBS, each with a 3.9 rating/10 share.

Fox grabbed almost a full rating point versus a year ago, in part because of new show "Glee" as well as the stronger numbers for "House."

CBS is up just one-tenth of a rating point. Key ingredients there were better results of "NCIS," "The Big Bang Theory" and its new "NCIS: Los Angeles."

NBC losses are from "The Jay Leno Show" appearance on a Monday to Friday basis -- with expected lower numbers than previous NBC dramas in the 10 p.m. time slot. Those shows averaged mid-two ratings a year ago. NBC's "Heroes" is down, as well as its Thursday night comedies.

But cable isn't the problem -- yet.

Ad-supported cable is down a tad over four days among 18-49 viewers in prime time: to a 16.8/45 from a 17.6/45. "Cable does try to get out of the way during broadcast premiere week," says David Scardino, entertainment specialist for Santa Monica-based media agency RPA Inc.

Last year, the five networks were down about 6% to 8% among 18-49 viewers, a bit higher than its historical trend.

All this should be looked at cautiously. TV analysts say the whole network fall TV marketing machine works well to get people sampling the new season and new shows in the first days of the season.

Says Scardino: "Basically, successful TV is about executing content over multiple episodes."