Check out this analysis.
The generic House ballot is tilting to Republicans in ways not seen… ever. Or as Michael Barone put it, the Republican margin currently seen is “historically unprecedented”. To those unfamiliar with the generic ballot, it is the question asked on national surveys that goes something like this “If the elections for Congress were being held today, which party’s candidate would you vote for in your Congressional district?” I have often (in my own head) questioned the usefulness of the generic ballot because House elections are held in districts not nationally, and surveys are only getting at most a few respondents from each district for each survey. But the fact of the matter is that vast majority of research indicates (see Charles Franklin, Matthew Shugart, and the Pew Research Center among others) that if you properly use the results from the question, you can get a pretty good idea of what is going to happen…Wow.
How will the generic ballot results from 2010 at this point translate into vote in the general election? Based off the Bafumi et al. regression (see page 6), we would expect Republicans to win the national vote by anywhere from 7.3% (all polls but Rasmussen and Republican pollsters) to 9.3% (all polls), which extends well beyond the root-mean-sqaured error. Thus, I have a hard time believing based off the polling that the Democrats will win the national party House vote…
With current polling in conjunction with Bafumi et al.’s paper predicting a Republican national vote between 53.6% and 54.7%, the Republicans could easily gain 50-60 seats from their current 178. Gains of greater than 60 seats also look quite possible. Even in the best case scenario for the Democrats, it would seem that holding the House would be very, very difficult.
Obviously, anything can happen between now and then, but you can't be anything less than happy with this trend, and the data backing it up.