Republican gains increasing in the House

Polly uses the high-profile application of election forecasting to demonstrate advances in forecasting methodology. According to Polly, the mean forecast for Republican gains in the U.S. House of Representatives has gone up over the last two weeks, from 44 to 48.

However, there's no change in the forecast for the Senate. Although it has bobbed up and down by one seat every few days, today the forecast is the same as it was two weeks ago.

It calls for the Democrats to emerge with 51 seats, for a net gain of 8 for the Republicans. That would leave the Upper House in control of the President's party. If so, this would be the first time in nearly a century that the House, but not the Senate, undergoes a party turnover.

The sources primarily responsible for the upward revision in the forecast are Rothenberg (up 4, from 41 to 45), Real Clear Politics (up 5, from 51 to 56), Cook (up 7, from 45 to 52), and Intrade (up 9, from 48 to 57).