HOW AMERICAN TV WORKS

In early development stage, American TV networks normally order pilots (the first one-hour or half-hour episode) based on the scripts they find the most promising. Following in-house screening at the network and focus group comments, they decide whether to pick-up the pilot or not. If so, they will give it an initial 13-episode order and find a place for it on the schedule.

All networks announce their new fall schedule at "The Upfronts" an event held each year for TV advertisers in New York. There, the networks present their new shows and schedules and announce which shows have been cancelled. The purpose of the event is to close contracts for TV advertising for the next season.

The networks try to sell as much of their advertising inventory as possible at the highest price possible. Those networks which have had problems with ratings are expected to make special offers to advertisers to compensate for lost viewers.

The schedule may change by the actual start of the new season in September, but most of the changes will occur after the first few weeks, once it becomes clear which new shows are hits, which deserve the second chance in a new timeslot, and which need to be taken off the schedule ASAP.

Strong performers normally have little patience for losers, hence the quick cancellation of "Smith" on CBS. If the show is however successful, it will get a full season pick-up for the back 9 episodes bringing the season total to 22. Only the most popular shows like "Grey's Anatomy", "Lost" or "Desperate Housewives" get more than 22 episodes per season (23-27).

Since the season ends in May (that's about 35 weeks in total) at least 13 weeks during the show's run from September to May will be repeats or pre-emptions (a different programme/special event airing in the same timeslot for one time only).

Many viewers in the US have however complained about this system for which reason the networks have started experimenting with uninterrupted runs of all original episodes (e.g., "24" on FOX airs January to May non-stop due to the highly-serialized nature of the programme).

The old system is however still firmly in place.