natina
10-28-2012, 05:51 AM
http://fivethirtyeight.blogs.nytimes.com/2012/10/27/oct-26-state-poll-averages-usually-call-election-right/
The FiveThirtyEight forecast model has found the past several days of battleground state polling to be reasonably strong for Barack Obama, with his chances of winning the Electoral College increasing as a result. The intuition behind this ought to be very simple: Mr. Obama is maintaining leads in the polls in Ohio and other states that are sufficient for him to win 270 electoral votes.
Friday featured a large volume of swing state polling, including three polls of Ohio, each of which showed Mr. Obama ahead by margins ranging from two to four percentage points.
Between Ohio and the other battleground states, Mr. Obama held leads in 11 polls on Friday, against four leads for Mitt Romney’s and two ties. Mr. Romney’s leads came in North Carolina and Florida, two states where the FiveThirtyEight forecast already had him favored.
To the extent that there was a trend in the state polls, it was slightly favorable for Mr. Obama. Among the eight polls that had previously published numbers after the first presidential debate in Denver, Mr. Obama gained about one percentage point, on average.
Mr. Romney made gains in four of the five polls that had last surveyed the race before Denver. Nevertheless, his average gain in the polls – 2.4 percentage points – was less than the 4-point bounce he was seeing in the immediate aftermath of the Denver debate. This suggests that Mr. Romney’s bounce has receded some (http://fivethirtyeight.blogs.nytimes.com/2012/10/25/oct-24-in-polls-romneys-momentum-seems-to-have-stopped/) since his post-Denver peak.
The national polls out on Friday were not terribly newsworthy. Mr. Obama had a miniscule lead of 0.2 points between the eight national tracking polls that were published, reversing an equally small 0.2-point advantage for Mr. Romney in the same surveys on Thursday.
You can see here (http://fivethirtyeight.blogs.nytimes.com/2012/10/11/oct-10-is-romney-leading-right-now/) my thoughts on reconciling the differences between state and national polls. They may be reflective of a potential split outcome between the popular vote and the Electoral College, but there are other plausible hypotheses as well. Specifically, it could be that the national polls slightly underrate Mr. Obama’s position, that the state polls slightly overrate it, or both.
The FiveThirtyEight forecast has Mr. Obama leading the popular vote along with the Electoral College, because it uses both state and national polls to calibrate its estimate of where the vote stands. Also, however, Mr. Obama’s state polls were adjusted slightly downward because his national polls remain middling.
Still, our state-by-state forecasts are extremely similar to those issued by our competitors. For example, we had Mr. Obama projected to win Ohio by 2.4 percentage points as of Friday. That compares to a 2.3 percentage-point lead for Mr. Obama in the Real Clear Politics average of Ohio polls, a 2.9-point advantage for him in the Huffington Post Pollster model, and a 2.7-point edge for him according to Talking Points Memo’s Poll Tracker.
How often does a lead of two or three points in the polling average, with 10 days to go until the election, translate into a victory in the state?
This is the sort of question that the FiveThirtyEight forecast is designed to address. But a simpler method is to just look at what happened when candidates held similar advantages in the past.
In the table that follows, I have attempted to recreate a simple polling average for competitive states in past elections, using about the same rules that Real Clear Politics applies.
In particular, I’ve looked at all states in our database in which there were at least three distinct polling firms that conducted surveys in the window between 10 days and three weeks before the election. Like Real Clear Politics, I used only the most recent poll (the one closest to the 10-day cutoff) if the polling firm surveyed the state multiple times during this period. I used the version of the poll among likely voters if it was available, defaulting to registered voter numbers otherwise.
http://fivethirtyeight.blogs.nytimes.com/2012/10/27/oct-26-state-poll-averages-usually-call-election-right/
http://www.gannett-cdn.com/media/USATODAY/USATODAY/2012/10/25/ap-obama-2012-4_3_r560.jpg?f061b7ce9937c38b702e6f308816ac2a14e2a 4ec
The FiveThirtyEight forecast model has found the past several days of battleground state polling to be reasonably strong for Barack Obama, with his chances of winning the Electoral College increasing as a result. The intuition behind this ought to be very simple: Mr. Obama is maintaining leads in the polls in Ohio and other states that are sufficient for him to win 270 electoral votes.
Friday featured a large volume of swing state polling, including three polls of Ohio, each of which showed Mr. Obama ahead by margins ranging from two to four percentage points.
Between Ohio and the other battleground states, Mr. Obama held leads in 11 polls on Friday, against four leads for Mitt Romney’s and two ties. Mr. Romney’s leads came in North Carolina and Florida, two states where the FiveThirtyEight forecast already had him favored.
To the extent that there was a trend in the state polls, it was slightly favorable for Mr. Obama. Among the eight polls that had previously published numbers after the first presidential debate in Denver, Mr. Obama gained about one percentage point, on average.
Mr. Romney made gains in four of the five polls that had last surveyed the race before Denver. Nevertheless, his average gain in the polls – 2.4 percentage points – was less than the 4-point bounce he was seeing in the immediate aftermath of the Denver debate. This suggests that Mr. Romney’s bounce has receded some (http://fivethirtyeight.blogs.nytimes.com/2012/10/25/oct-24-in-polls-romneys-momentum-seems-to-have-stopped/) since his post-Denver peak.
The national polls out on Friday were not terribly newsworthy. Mr. Obama had a miniscule lead of 0.2 points between the eight national tracking polls that were published, reversing an equally small 0.2-point advantage for Mr. Romney in the same surveys on Thursday.
You can see here (http://fivethirtyeight.blogs.nytimes.com/2012/10/11/oct-10-is-romney-leading-right-now/) my thoughts on reconciling the differences between state and national polls. They may be reflective of a potential split outcome between the popular vote and the Electoral College, but there are other plausible hypotheses as well. Specifically, it could be that the national polls slightly underrate Mr. Obama’s position, that the state polls slightly overrate it, or both.
The FiveThirtyEight forecast has Mr. Obama leading the popular vote along with the Electoral College, because it uses both state and national polls to calibrate its estimate of where the vote stands. Also, however, Mr. Obama’s state polls were adjusted slightly downward because his national polls remain middling.
Still, our state-by-state forecasts are extremely similar to those issued by our competitors. For example, we had Mr. Obama projected to win Ohio by 2.4 percentage points as of Friday. That compares to a 2.3 percentage-point lead for Mr. Obama in the Real Clear Politics average of Ohio polls, a 2.9-point advantage for him in the Huffington Post Pollster model, and a 2.7-point edge for him according to Talking Points Memo’s Poll Tracker.
How often does a lead of two or three points in the polling average, with 10 days to go until the election, translate into a victory in the state?
This is the sort of question that the FiveThirtyEight forecast is designed to address. But a simpler method is to just look at what happened when candidates held similar advantages in the past.
In the table that follows, I have attempted to recreate a simple polling average for competitive states in past elections, using about the same rules that Real Clear Politics applies.
In particular, I’ve looked at all states in our database in which there were at least three distinct polling firms that conducted surveys in the window between 10 days and three weeks before the election. Like Real Clear Politics, I used only the most recent poll (the one closest to the 10-day cutoff) if the polling firm surveyed the state multiple times during this period. I used the version of the poll among likely voters if it was available, defaulting to registered voter numbers otherwise.
http://fivethirtyeight.blogs.nytimes.com/2012/10/27/oct-26-state-poll-averages-usually-call-election-right/
http://www.gannett-cdn.com/media/USATODAY/USATODAY/2012/10/25/ap-obama-2012-4_3_r560.jpg?f061b7ce9937c38b702e6f308816ac2a14e2a 4ec