Predicting the decline in the broadcast network prime-time audience for the upcoming 2009-10 season is a bit like shooting fish in a barrel. After all, broadcast networks have been losing primetime audience to ad supported cable networks for more than a generation.
However, I'd expect declines to be even more substantial than last season's (see chart below) for two primary reasons:
1. Accountants, Not Ratings, Making Renewal Decisions. The number of below average rated shows brought back from 2008-9 for primarily economic reasons is greater than it was from 2007-8. That will start those broadcasters in a ratings hole.
2. The Jay Leno Show. NBC is abandoning a portion of its weekday 10-11 ratings and knows it.
Prediction: This season I'd expect audience declines to average 10% for broadcast primetime.
A few extraordinary things will (or could) boost the numbers we see:
1. The Winter Olympics. NBC will get a massive boost from the two weeks of Winter Olympics in February. I'll pull that boost out of ratings comparisons as best I can. Don't count on the rest of the TV media (or god knows, NBC PR) to do that though.
2. Baseball Playoffs / World Series. If Fox gets long series between popular teams their averages can be boosted tremendously. Last fall they had relatively bad luck (TNT had better luck with their games), so good luck this season could produce some upside. Unfortunately, with the data I get I can't do a good job of isolating.
3. CW abandons Sunday night. As I already covered, this is pretty much guaranteed to boost the CW's averages no matter what happens to their weekday ratings.
Here's what happened last season:
In the chart above, I have adjusted the NBC numbers to remove the effects of Super Bowl week 2009 and adjusted the Fox numbers to remove the effects of Super Bowl week 2008. My adjustments remove the effect of the entire week, not just the game, so they're crude, but they make season to season comparisons at least reasonably possible. With the data I have available I cannot make a finer adjustment.