Generally, not massively. As I said a few days ago when United odds dropped dramatically. A big change normally happens when someone places on a huge bet on something (perhaps based on inside information, perhaps based on rumour) and the bookies change their odds to avoid loosing a lot of money. The bookies haven't particularly got inside information themselves, though SkyBet must be based on Skys 50/50 credible sources. As someone else said yesterday, odds were suspended on Harry Redknapp getting the Chelsea job in 2011 before AVB. So clearly, often wrong. BUT, 1/4 to 1/100 in the space of a few hours is oddly dramatic.