Measuring the effects of shark-jumping

Annalee Newitz at io9 has produced a chart allegedly showing that ratings for "Battlestar Galactica" declined immediately after episodes in which the show jumped the shark. This analysis is critiqued by Chris Lawrence, who gets all geeky and finds no statistically significant effect of shark-jumping on subsequent ratings.

I respect the nerdiness at work here, but there are a few problems with this line of inquiry. For one thing, Newitz uses a viewer poll that identifies seven episodes in which BSG jumped the shark. This, to me, suggests no clear consensus. All they've identified are episodes that weren't particularly good, like the boxing one. I would suggest that the show never jumped the shark, except maybe in the final 30 minutes of the final episode, when the show had, by its own standards, completed its story arc (more on that later).

My definition of shark-jumping is when a show has clearly lost its mission -- whether that's to convey a message, to shake up the status quo, or just to entertain -- and now exists just for the sake of its own existence.

Clear instances of shark-jumping, in my opinion:

• The eponymous one, when Fonzie jumped a shark.
• When all the Walshes left "90210," eradicating the entire point of the show.
• The addition of 7 of 9 to "Star Trek: Voyager" may have been a jump, in that it was a craven acknowledgment that a sci-fi show couldn't survive without a hottie. But they actually built some nice stories around her so I think they recovered a bit.
  

The quantitative analysis, as a friend of mine pointed out, has the additional problem in that they're selecting the independent variable (shark-jumping episodes) retroactively on the dependent variable (declining ratings). That is, we hard core fans all agree that a show has jumped the shark when we stop watching it. So to look for an "effect" is a bit disingenuous.