The polls were off in Maryland by 20 points: Hogan won by 10, and polls showed him behind by 10.  The Virginia Senate race off by 10.

On average, GOP candidates beat polling average by 5 points in close Senate races, and by 3 in close governors’ races – almost the reverse of 2012, when Dems over-performed.

Midterms in general are off by more than polls in presidential years.  Pollsters always adjust their raw results to achieve mixes of Dems and Republicans, various age groups, parts of a state, etc.  Those adjustments suggest that patterns are fixed – but they are not.

Republicans over-polled for a few cycles, because cell phone users were undercounted.  It is possible that the adjustment for that this time was too high in an off-year, with higher GOP enthusiasm.

The Maryland result is a reflection of what a loser O’Malley is as governor.  He makes Thomas Carcetti from The Wire, a character reputedly loosely based on him, look respectable.