Direckshun

09-20-2012, 09:27 PM

Obama's extremely likely to win at this point. The Senate is now pretty likely to stay Democratic.

Now there's a chance the Dems could grab enough seats to take the House.

Tons and tons of links in the piece.

http://election.princeton.edu/2012/09/20/house-outlook-for-2013-take-2/

Republicans at risk of losing the House?

by Sam Wang

September 20th, 2012, 10:00am

As seen in recent articles in Politico and U.S. News, few pundits think the Democrats will re-take the House. However, analysis of a leading indicator suggests to me that transfer of control is a distinct possibility.

Predicting the House outcome is challenging. First, there is the basic problem that we have to estimate how far opinion will move between now and November. On top of that, there is uncertainty in knowing how the polling measurement – generic Congressional ballot preference – translates to a seat outcome.

Another approach would be to use district-by-district polls and ratings. An estimate like that can be seen from our data partner, Pollster.com. Their House outlook shows retained GOP control, and RealClearPolitics implies the same. However, many of those polls are weeks or months old. My estimate today suggests that in the coming weeks, we might look for district polls to move in the Democrats’ direction. This is also an opportunity for a detailed analytical approach, as taken elsewhere, to shine.

In 2010, the national Congressional vote was a big 6.6% margin of popular vote win for the Republicans. That outcome was very close to the pre-election R+7% polling median (but 8 points less than the final Gallup poll of R+15%). So the generic Congressional preference poll, aggregated across pollsters, can give some sense of where the vote will go.

In 2012, the picture looks very different from 2010. Congressional voter sentiment before Labor Day is often movable (see 2008 and 2004 history). But we are now entering the high season, so some sense of the outcome is starting to emerge.

In summer polls leading up to the 2012 conventions, Republicans were behind Democrats by a median of 2%, a 9-point swing from 2010. Consequently, many seats won in that Republican wave are now at risk, as I pointed out in my previous House outlook. To put it another way, midterm election conditions (as in 2010) work against incumbent Presidents; the pendulum has now swung back.

http://election.princeton.edu/wp-content/uploads/2012/09/house-generic-19sep2012.jpg

In post-convention polls, Democrats got a big bounce that peaked at D+6% and now appears to be subsiding. It is a good thing for the Republicans that the election was not last week. The most recent polls (Sept. 7-17) indicate a median lead of D+4.0+/-2.0% (+/- estimated SEM, n=7 different pollsters). (Note that the HuffPost smoothing software uses a different algorithm.) This 11-point swing from 2010, if it were to hold, would lead to big Democratic gains in the House.

As I pointed out two weeks ago, the eventual national D-minus-R House popular vote share is strongly predictive of the corresponding margin of House seats. Here is a graph based on data from 2000-2010 House elections.

http://election.princeton.edu/wp-content/uploads/2012/08/house-2000-2010-national-seats-vs-margin.jpg

It shows that each 1.0% of popular-vote margin translates to a 6.0-seat advantage. This plot shows no long-term advantage* for either side: a nearly-tied popular vote would translate to a nearly-tied House (x-intercept = -0.3 +/- 1.1%). Individual data points deviate from the fit line by 7 to 17 seats in either direction.

However, there is a known advantage to incumbency, which I estimate as being worth an equivalent of 1.3 +/- 1.0% of popular vote. This is smaller than a recent estimate**. In other words, on average a national win of D+1.3% is required for the House to change hands.

Next, let us translate the generic Congressional ballot to estimate House seat outcomes. Applying the Wisdom-of-Pollster-Crowds principle that has served so well in Presidential and Senate races, we will use the poll median to approximate the actual popular preference.

The HuffPost graph above includes telephone polls (i.e. not robopoll or Internet), but that is strictly for purposes of clear display. Using all polls and median-based statistics to address issues of outlier data gives the median of D+4.0% that I gave. That translates to a narrow 16-seat Democratic majority in an election held today.

This would be an unusual outcome. It would involve a Democratic net pickup of over 30 seats, much more than the typical gain for a re-elected president’s party. But 2010 was also an exceptional wave year for the Republicans. Again, think of the pendulum. In any event, this is what the numbers are currently telling us.

The principal caveat. The main issue with this analysis is that it does not use district-level data. In the coming weeks, those surveys will become more abundant. In 2008, district polls did a very good job of estimating the outcome – on Election Eve. Six weeks out, the generic ballot preference is the week-to-week indicator that is available.

Where things could go in the next seven weeks. Assume a +/-4% opinion shift between now and November, and this leads to a popular vote prediction of D+0% to D+8% (1 sigma). This gives a Democratic takeover probability of 74%, approximately three out of four.***

It should be noted that current conditions emphasize the post-convention bounce, which could be transient. Conversely, if the Democratic lead increases, that would take House control out of the knife-edge territory that I defined previously. For now, a smart use of campaign donations is to donate to the DCCC through this ActBlue page, or the GOP through Crossroads GPS.

Now there's a chance the Dems could grab enough seats to take the House.

Tons and tons of links in the piece.

http://election.princeton.edu/2012/09/20/house-outlook-for-2013-take-2/

Republicans at risk of losing the House?

by Sam Wang

September 20th, 2012, 10:00am

As seen in recent articles in Politico and U.S. News, few pundits think the Democrats will re-take the House. However, analysis of a leading indicator suggests to me that transfer of control is a distinct possibility.

Predicting the House outcome is challenging. First, there is the basic problem that we have to estimate how far opinion will move between now and November. On top of that, there is uncertainty in knowing how the polling measurement – generic Congressional ballot preference – translates to a seat outcome.

Another approach would be to use district-by-district polls and ratings. An estimate like that can be seen from our data partner, Pollster.com. Their House outlook shows retained GOP control, and RealClearPolitics implies the same. However, many of those polls are weeks or months old. My estimate today suggests that in the coming weeks, we might look for district polls to move in the Democrats’ direction. This is also an opportunity for a detailed analytical approach, as taken elsewhere, to shine.

In 2010, the national Congressional vote was a big 6.6% margin of popular vote win for the Republicans. That outcome was very close to the pre-election R+7% polling median (but 8 points less than the final Gallup poll of R+15%). So the generic Congressional preference poll, aggregated across pollsters, can give some sense of where the vote will go.

In 2012, the picture looks very different from 2010. Congressional voter sentiment before Labor Day is often movable (see 2008 and 2004 history). But we are now entering the high season, so some sense of the outcome is starting to emerge.

In summer polls leading up to the 2012 conventions, Republicans were behind Democrats by a median of 2%, a 9-point swing from 2010. Consequently, many seats won in that Republican wave are now at risk, as I pointed out in my previous House outlook. To put it another way, midterm election conditions (as in 2010) work against incumbent Presidents; the pendulum has now swung back.

http://election.princeton.edu/wp-content/uploads/2012/09/house-generic-19sep2012.jpg

In post-convention polls, Democrats got a big bounce that peaked at D+6% and now appears to be subsiding. It is a good thing for the Republicans that the election was not last week. The most recent polls (Sept. 7-17) indicate a median lead of D+4.0+/-2.0% (+/- estimated SEM, n=7 different pollsters). (Note that the HuffPost smoothing software uses a different algorithm.) This 11-point swing from 2010, if it were to hold, would lead to big Democratic gains in the House.

As I pointed out two weeks ago, the eventual national D-minus-R House popular vote share is strongly predictive of the corresponding margin of House seats. Here is a graph based on data from 2000-2010 House elections.

http://election.princeton.edu/wp-content/uploads/2012/08/house-2000-2010-national-seats-vs-margin.jpg

It shows that each 1.0% of popular-vote margin translates to a 6.0-seat advantage. This plot shows no long-term advantage* for either side: a nearly-tied popular vote would translate to a nearly-tied House (x-intercept = -0.3 +/- 1.1%). Individual data points deviate from the fit line by 7 to 17 seats in either direction.

However, there is a known advantage to incumbency, which I estimate as being worth an equivalent of 1.3 +/- 1.0% of popular vote. This is smaller than a recent estimate**. In other words, on average a national win of D+1.3% is required for the House to change hands.

Next, let us translate the generic Congressional ballot to estimate House seat outcomes. Applying the Wisdom-of-Pollster-Crowds principle that has served so well in Presidential and Senate races, we will use the poll median to approximate the actual popular preference.

The HuffPost graph above includes telephone polls (i.e. not robopoll or Internet), but that is strictly for purposes of clear display. Using all polls and median-based statistics to address issues of outlier data gives the median of D+4.0% that I gave. That translates to a narrow 16-seat Democratic majority in an election held today.

This would be an unusual outcome. It would involve a Democratic net pickup of over 30 seats, much more than the typical gain for a re-elected president’s party. But 2010 was also an exceptional wave year for the Republicans. Again, think of the pendulum. In any event, this is what the numbers are currently telling us.

The principal caveat. The main issue with this analysis is that it does not use district-level data. In the coming weeks, those surveys will become more abundant. In 2008, district polls did a very good job of estimating the outcome – on Election Eve. Six weeks out, the generic ballot preference is the week-to-week indicator that is available.

Where things could go in the next seven weeks. Assume a +/-4% opinion shift between now and November, and this leads to a popular vote prediction of D+0% to D+8% (1 sigma). This gives a Democratic takeover probability of 74%, approximately three out of four.***

It should be noted that current conditions emphasize the post-convention bounce, which could be transient. Conversely, if the Democratic lead increases, that would take House control out of the knife-edge territory that I defined previously. For now, a smart use of campaign donations is to donate to the DCCC through this ActBlue page, or the GOP through Crossroads GPS.