… At present, Republicans hold a 247 to 186 seat majority in the House of Representatives (with vacancies in two formerly Democratic-held seats that the party will easily hold onto). All 435 House seats and 34 of the 100 Senate seats are up for election this year. In reality, however, only around 50 House seats and perhaps a dozen Senate seats are really in play — the rest are completely safe for one party or the other. Nevertheless, there are enough seats in play that there is some uncertainty about which party will end up in control of the House and a great deal of uncertainty about which party will end up in control of the Senate.
So what should we expect in the House and Senate elections this year? A simple forecasting model based on three predictors — the number of Republican seats at stake in the election, support for the two major parties on the “generic ballot” question in national polls, and whether it is a midterm election under a Democratic or Republican president — yields fairly accurate predictions of seat swing in the House and Senate. CONT.
Alan I. Abramowitz, Sabato’s Crystal Ball