It's important to remember that Gallup offers this up as a predictor of the aggregate national vote for the parties, which does not translate into how many seats each will win, given that the vote is spread over 435 districts. Voters may be in a Republican or Democratic mood, but when it comes to an actual name on the ballot, their decision may be different. And, another variable is how many voters actually turn out at the polls.
Gallup says, based on its statistical model, that the Democrats could lose the overall 2010 congressional vote and keep their House majority. If the Democrats garner 51 percent of the national vote, Gallup's prediction is that they could hold on to almost all their current seats, and with as little as 48 percent of the vote, still retain a majority of 218 members.
The model developed by Gallup uses historical voting patterns in midterm elections since 1946 and other factors, such as who holds the White House and House at the time of the election.




