Generic Ballot

A new CNN/Opinion Research poll has the Democrats with a 4 point edge in the generic ballot. Already a few Democratic friends are imagining their party taking back the House.

The problem is that this assumes that a 4 point lead in the generic ballot will produce a 4 point win on election day. That's unlikely.

The poll is with registered voters, not actual voters. Democrats tend to do better with registered voters than likely/actual voters. Blacks, Hispanics, Asians, and young people vote below their share of the electorate, even in Presidential years. The registered voter polls will likely overstate Democratic performance. Democrats were leading in the generic ballot by 12-14 points for most of 2007 into 2008. That number dropped when they went to the likely voter model, before going up after the fiscal crisis.

Even after the likely voter model is used Democrats tend to underperform it. In 2004, the generic ballot was a tie, but Republicans won by 2.5 points. In 2006 Democrats were ahead by 11.5 points in the generic ballot and won by 7.9.

The next factor is that the Democratic percentage of the vote hasn't been reflected in their seat total. After each election from 1996 to 2006 Democrats had a lower percentage of seats than their total House vote. In 1996 they even took a majority of the vote, but still managed only 206 seats.

One explanation for this is that Democrats have been packed in a smaller number of congressional districts during redistricting. Currently there are 234 Republican leaning districts, but there are only 192 Democratic leaning districts. With Republicans controlling redistricting, there likely will be more than 234 Republican leaning districts. Republicans won't have to do much to retain at least 218 seats.