Bafumi, Erikson and Wlezien predict 50-seat loss for the Democrats

Via Memeorandum
Previewing the first scholarly assessment of the upcoming House elections expected to be published in the October issue of PS: Political Science, Bafumi et al predict a Republican takeover of the House:

Our forecast, based on information gathered in early July 2010, is a likely Republican takeover of the House. In terms of the national vote, the most likely outcome is a solid Republican plurality of close to 53% of the two-party vote. Damage to the Democrats is minimized somewhat in the translation of votes into seats. By our reckoning, the most likely scenario is a Republican majority in the neighborhood of 229 seats versus 206 for the Democrats. Assuming our model is correct but taking into account its uncertainty, the Republicans have a 79% chance of winning the House.

Now for the caveats:

Applying our model to 2010 assumes that the forces at work in 2010 are unchanged from past midterm elections. However, we should be wary of the possibility that the underlying model of the national vote works differently in 2010 or is influenced by variables we have not taken into account. Because the 2010 campaign started to heat up earlier than usual, the usual tilt toward the out party may already be complete, with no further drift to the Republicans. It is also uncertain how voters will react to the tea-party movement as the public face of the Republican Party.

The key will be to follow the generic polls from now to November. If the polls stay close, the Democrats have a decent chance to hold the House. But if the polls follow the past pattern of moving toward the "out" party and move further toward the Republicans -- even by a little -- the Republicans should be heavily favored. 

Thus far, generic polls taken since July 2010 have drifted towards Republicans including this week's Gallup generic ballot that favored Republicans by a 10 point margin, the largest in Gallup's 60 year history.  As yet, there doesn't appear to be any evidence Republicans have peaked too early or that independent voters will suddenly vote in backlash to the tea-party movement.

Bafumi attended the annual meeting of the American Political Science Association.  Three of five political scientists forecasted Republicans gaining 49 to 52 seats.  Bafumi's high number for Republican pick-ups was 57 based on his two variable model.  He argued the results of midterms are generally baked in the cake quite early in the election year:

Remarkably, forecasts from our two variables—the generic poll results and the party of the president—are about equally predictive regardless of when the poll results are taken. In short, the midterm vote tends to be determined early, with the campaign serving mainly to draw the voters toward the out-party. Taking into account election-year changes in the president’s approval rating or economic conditions has not offered any improvement in the forecast equation in the past (Bafumi et al. 2010).

A 50 seat loss for Democrats would certainly make a certain witch we know quite unhappy.  What a world,  what a world!   It remains to be seen whether such a loss would be sufficient to teach an old dog some new tricks - let's just say I doubt it.