A few days ago, prior to the election, I noted some issues that were on tap for yesterday's midterm election in the US and now we have answers to at least some of the questions raised. In California we know that Proposition 20 passed which now gives a citizens commission created two years the power to draw congressional district boundaries in California, as well as the state legislative boundaries. This is designed to "take the politics out" of the redistricting process. At the same time, Proposition 27 in California failed, which is important because it aimed to eliminate the citizens commission altogether and hand the redistricting responsibilities back to the legislature. Since the Republicans generally won more gubernatorial and congressional seats than did Democrats, it is likely that this cascaded down to state legislatures (although I cannot confirm that of this writing) and so this should put Republicans in more advantageously drawn congressional districts in the 35 states that continue to have this task undertaken by legislative bodies rather than citizens commission. Of course, redistricting is not an issue in the seven states that still have only one member of the House of Representatives due to their small population--Alaska, Delaware, Montana, North Dakota, South Dakota, Vermont, and Wyoming.
No one has yet had a chance to do an in-depth analysis of the relationship between pre-election polling and the actual results, but it appears that in some high-profile controversial races, such as that between Harry Reid and Sharron Angle in Nevada, the gap in the final results was considerably larger than had been projected based on pre-election polling. This could be due to changes in voter's minds, but it could also have been due to inappropriate weighting of demographic groups in terms of their likelihood of voting.