Sam Wang - Princeton Consortium - his take on the disappointing (for us) results
http://election.princeton.edu/
Midterm Polls Strike Again!
November 5th, 2014, 11:41am by Sam Wang
Pre-election PEC Senate aggregate: 52 Republican seats.
Outcome: 53 or 54 Republican seats (Louisiana goes to a runoff).
"Last nights performance by the GOP was remarkable. In close Senate races, Republicans outperformed polls by an average of 5.3 percentage points. Prime examples of that effect could be seen with Republican wins in Kansas and North Carolina, two races that went against pre-election polls.
In gubernatorial races, Republicans outperformed polls nearly 2 percentage points on average. This was enough to put Paul LePage of Maine (tied), Rick Scott of Florida (tied), and Bruce Rauner of Illinois (Quinn +2.0%) over the top. All in all, Republicans had an excellent night.
Historically, midterm polling is much more prone to large biases than in Presidential years. In 2010, Democrats benefited; in 2014, it was Republicans. In six Senate races that were polling within less than three percentage points, two were won by the lagging candidate. That is entirely in line with past results. Added to the median poll-based snapshot of 52 Republicans, 48 Democrats+Independents, the result is a convincing 54-46 majority."
snip - lots more graphs, analysis, etc