Way Late 2010 Election Prediction Analysis

I was thinking about doing another House of Representatives prediction.  Since my last prediction hit the Republican gain exactly, and I did not do a full gloating analysis post, I am doing that first.

While my overall prediction last time of a 63-seat gain for the Republicans was exactly right, I did miss about 8-12 seats in both directions, so my actual prediction may not have been that great.

I think there were three causes of my missed predictions.

 1.  I just did not have enough knowledge about individual candidates.  For instance I picked the Republicans to win Arizona 8, but Gabrielle Giffords was probably a much more appealing candidate than was apparent to me as an outsider, and she held it for the Dems.

2.  My main point that I missed for the Republicans was their strong showing in the suburbs.

3.  The main thing I missed for the Democrats was that I expected African-American turnout to drop more than it did.

Those last two things only affected a couple of races each.  The truth is that there are actually very few true suburban districts.  Either they are suburban-urban and therefore solid Democratic or suburban-exurban and solid Republican.  Very few districts are suburban and thus toss up.  The few seats like this are concentrated around New York and Chicago.  With majority-minority districts, there are not very many districts where African-Americans make up a sizable but not determinative proportion of the electorate.