I think each celeb starts with a natural constituency of existing fans who are also SCD fans. And, if your natural constituency is large enough this will carry you quite a long way even if you are not the best dancer. Also, if, like Lisa or Jon Sargeant, you attract a strong personal vote for whatever reason this will also carry you a long way.

But as each celeb drops away there personal support becomes radicalised and will look for a new home which I think is going to be disproportionately based on who had proven to be the better dancers.

So, your core vote remains but the better dancers start picking up transfers from other ousted celebs.