With the midterm elections now just nine weeks away, a group of political scientists gathered for a conference in Washington D.C. this weekend forecast significant losses for the Democrats. Three of the five forecasts predicted that Republicans will gain majority control of the House of Representatives.
The annual meeting of the American Political Science Association (APSA), which featured nearly 5,000 participants and close to 900 panel and roundtable sessions, was about far more than election forecasting. Those most interested in the 2010 campaigns, however, gravitated to a Saturday session in which five political scientists presented the latest results from their forecasting models, some of which have been in development for 30 years or more.
Democrats currently hold a 256 to 179 seat advantage, so Republicans need to win at least 39 seats to gain majority control. Three of the models, two of which draw on national polls measuring whether voters plan to support the Democrat or Republican candidate in their district, point to Republicans picking up between 49 and 52 seats in the House, more than enough to win majority control. Specifically:
- Alan Abramowitz of Emory University forecast a Republican gain of 49 seats, based on current polling showing Republican with a roughly five percentage-point lead on the generic House ballot.
- Joe Bafumi of Dartmouth College presented his forecast of a 50-seat Republican gain, based on a model and paper co-authored with Robert Erikson of Columbia University and Chris Wlezien of Temple University (and summarized last month in the Huffington Post). Their model also rests heavily on national polling on U.S. House vote preferences.
- James Campbell of SUNY Buffalo predicted a gain of 50 to 52 seats for the Republicans, using a model that combines assessments of the number of "seats in peril" by the Cook Political Report with the recent job approval rating of president Barack Obama.
Two more models offered a less pessimistic outlook for the Democrats:
- Alfred Cuzan forecast a Republican gain of 27 to 30 seats based on a model, developed with University of West Florida colleague Charles Bundrick, that relies mostly on measures of economic growth and inflation rather than voter preference polling.
- Michael Lewis Beck of the University of Iowa predicted a Republic gain of just 22 seats. He collaborated with Charles Tien of CUNY Hunter College on a more than 30-year-old "referendum" model based on measurements earlier this year. Their model was the only one to exclude measurements of the current seat division between Democrats and Republicans.
Why so much variation in the forecasts? Another speaker, Gary Jacobson of the University of California San Diego, pointed out that the number of previous elections typically used by forecasters (typically between 16 and 32) is "not a very big number," while a great many "plausible" predictive measures exist. Moreover, the national polling numbers used by the modelers are often "really, really noisy."
Jacobson also noted the differences between the "fundamentalist" models of Cuzan/Bundrick and Lewis-Beck/Tien that assume that views of the the economy and the Obama administration drive voting, and the others that use vote preference questions which, as he put it, "add in the information that's already the product of these fundamentals" as well as "the other stuff that's going on" with voter preferences.
Lewis-Beck argued that the "the best models are based on theory ... things that we know [or] that we're pretty certain we know," which in this case means the belief that "people vote about the main direction of the economy, and they vote about big macro political issues," especially in midterm elections.
At least one of the academics noted the apparent gap between what the fundamentals alone predict and what the polls are picking up. "Republicans are polling a lot better than they should be," Bob Erikson argued, "by [the] fundamentals."
Correction: The original version of this article misstated Chris Wlezien's academic affiliation.