The Playing Field Shifts: Predicting the Seats-Votes Curve in the 2008 U.S. House Election (with Andrew Gelman and Jamie Chandler). 2008. PS: Political Science & Politics. 41(4):729-32.

 

Abstract: This paper predicts the seats-votes curve for the 2008 U.S. House elections. We document how the electoral playing field has shifted from a Republican advantage between 1996 and 2004 to a Democratic tilt today. Due to the shift in incumbency advantage from the Republicans to the Democrats, compounded by a greater number of retirements among Republican members, we show that the Democrats now enjoy a partisan bias, and can expect to win more seats than votes for the first time since 1992. While this bias is not as large as the advantage the Republicans held in 2006, it is likely to help the Democrats win more seats than votes and thus expand their majority.

Click here to download a pdf copy of the paper.

Click here to visit the replication page for the paper.

Click here for our paper predicting the 2006 seats-votes curve.

 

Post-Election Analysis

We re-estimated the seats-votes curve after the election using information on uncontested races.   An updated version of Figure 1 in the paper appears below, along with the actual election results and seat shares.  As the left figure makes clear, the Democrats won less seats in 2008 than our seats-votes curve predicted, even though they significantly increased their overall seat share.  For more analysis on the House races, see here, here and here.