Which CBS TV shows will be cancelled or renewed for the 2011-12 season? The networks make their decisions largely based on the ratings, particularly the 18-49 demographics. Much of the CBS schedule has been in repeats recently but let’s take a look at how the few originals performed.

On Wednesday, Paula Abdul’s Live to Dance continued to fall and attracted just a 1.0 rating in the demo and 4.512 million viewers. Its funny to think that, a few years ago, Abdul was getting so many more viewers over on FOX’s American Idol.

Criminal Minds was up by 10% and Blue Bloods was up by 5%. That’s the second episode for Blue Bloods since moving to Wednesdays. It’s seen an improvement over its Friday numbers but so far isn’t doing much better than former timeslot occupant The Defenders.

On Thursday, without a Big Bang Theory original as a lead-in, $#*! My Dad Says was down by 3.4% in the demo. The rest of the night was in repeats.

You can see a complete list of the current status of this season’s shows by checking the CBS cancelled/renewed post.

Below is a list of the regular CBS TV shows and their 2010-11 season average ratings to date. It only incorporates the ratings for original episodes that have aired this season (no repeats). The data is sorted by the 18-49 demographic averages, the group that advertisers will pay the most to reach and, therefore, how the network measures success. The “compared to” column reflects whether the demo average has gone up, down, or stayed the same since last week.

The closer a show is to the bottom of the list, the closer it is to being cancelled (if it hasn’t been cancelled already like Medium). If it’s closer to the top of the list, it’s more likely to be renewed. Shows that are in the middle (“on the bubble”) can be a little tougher to call. Their future typically comes down to other factors like overall costs, contracts, who produces the show, and what new shows are on the horizon.

The list has been separated into two sections. Of the two, scripted programming is the most expensive to produce. News and reality TV shows are less expensive to make but the networks can’t program just news/reality (though they might like to since they are less of a financial risk).

It should be noted that Friday and Saturday nights are the least watched evenings of television so ratings for shows on those nights are lower. The networks understand this and take it into account. However, regardless of when a show is aired, its production costs remain the same. Ultimately, it must still be profitable enough for the network to keep ordering more episodes.

Raw data: © The Nielsen Company via Media Week. * Nielsen doesn’t release the final Friday and Saturday night ratings until a few days later. Numbers with an “*” may change slightly once the final numbers are released.

What do you think? Which shows do you think won’t survive to see a new season?

Image courtesy CBS.