Mark Blumenthal, Ariel Edwards-Levy, Natalie Jackson --- The Huffington Post
In 2014, the high-stakes battle for control of the U.S. Senate, rather than individual House races, has gotten most of the attention from pollsters and the news media. However, the most recent data from national and district-level surveys suggests that while they're polling significantly behind the level of the 2010 GOP wave, Republicans are poised to expand their U.S. House majority on Tuesday, gaining at least a half dozen seats and perhaps as many as 10 to 15.
Compared to the U.S. Senate races, publicly released polling at the level of individual U.S. House seats is rare. Heading into the final weekend of campaign 2014, for example, HuffPost Pollster had found less than a dozen House contests for which 5 or more polls have been released publicly.
On Friday, CBS News, in partnership with The New York Times and the online pollsters YouGov, asked voters in all 435 U.S. House Districts about which candidate they are planning to support for U.S. House, with larger samples for the most competitive districts. The poll predicted that Republicans will gain between 6 and 12 seats in the House. Interviews were conducted with respondents drawn from YouGov's opt-in panel of Internet-based respondents. To help bolster their estimates, YouGov also combined the survey responses with “fundamentals” about the district, including past votes for Congress and president, campaign spending, and whether the race features an incumbent seeking reelection.
While it is unusual to have district-by-district data, there is also a broader way of looking at which party will win the House: the "generic vote" question used by national pollsters, which typically asks poll respondents to say whether they would vote for "the Democratic Party's candidate or the Republican Party's candidate" if the election were held today, not taking into account the actual candidates running for office or even whether an incumbent may be running unopposed. (Some also ask a more general question about what party voters would prefer control the U.S. Congress.) While the generic vote question is something of blunt instrument, pollsters and political scientists consider it to be a reasonable predictor of national voting.