[gizmo686]

You can view a bit of their analysis here: https://projects.fivethirtyeight.com/checking-our-work/presi...

Their seems to be a systemetic bias for them to be underconfident. That is to say, when they a result is likly (>50%) to happen, they underestimate how likely. Conversly, when they think an event is less likely (<50%), they overestimate its chances. Still, more likely events tended to occur more often than less likely events.

Correcting for this systematic error would mean they should have given Clinton an even higher chance.