Polling - Predictwise Blog

2014 Election

A closer look at that GOP over-performance

There are 35 senate elections (excluding Louisiana) and 36 gubernatorial elections. We had expected vote shares for all of them, in terms of two-party vote share, which were primarily generated from traditional polling. In 54 of 71 (76%) elections the Republican candidate over-performed (28

2014 Election

Overall Calibration Pretty Good ...

In a preliminary look at Election Eve predictions for the 507 elections, we did pretty well. Senate (34 of 35): I am going to hold out Louisiana for now and assume there were 35 elections. In those 35 election we had the binary winner

2014 Election

Election Night 2014

1:30 AM ET: This is what under-performance versus the polls looks like: 10:33 PM ET: 10:13 PM ET: We have the senate at 95% for the Republicans, but that almost feels generous to the Democrats. 8:07 PM ET: The Democrats

2014 Election

Microsoft Prediction Lab's final probabilities

Five weeks ago I launched a new website, with a few friends, including Miro Dudik and David Pennock, called Microsoft Prediction Lab. The website consolidates research into both non-representative polling and prediction games. I have spent years understanding how various raw data: polling, prediction

2014 Election

Democrats poised for (possible) great night … in governors elections

The Democrats have a decent chance at having a great night in the governor’s races. There are 10 elections that I am following closely: 2 Tough, but possible pickups for the Democrats: Wisconsin: this is a potentially a huge pick-up for the

2014 Election

Republicans at about 85% to capture U.S. Senate

The Republicans are about 85% likely to take control of the U.S. Senate in January, 2015. This is going to happen, because the Democrats are going to win Blue States and the Republicans are going to win Red States. And, the Republicans are

2014 Election

Hidden Errors and Overconfident Pollsters

Written with Sharad Goel and Houshmand Shirani-Mehr Election forecasts, whether on HuffingtonPost's Pollster, New York Times’ Upshot, FiveThirtyEight, or PredictWise, report a margin of error of typically 3 percentage points. That means that 95% of the time the election outcome should

Polling

The health care debate: popularity, probability, and facts (Originally posted on Yahoo!'s "The Ticket" Blog)

What do you regard as the most important factor in the health care debate? If I wade into this question, would you prefer to hear more about what the public thinks, what the likely outcomes ahead may be–or what the law itself

Polling

Herman Cain’s star is rising–everywhere but in the prediction markets (Originally posted on Yahoo!'s "The Ticket" Blog)

Herman Cain is rising in the polls of Republican primary voters, but prediction markets are not buying into the Cain surge. On Wednesday evening, MSNBC led its web page with the breaking news that the network’s latest poll showed Cain atop the

Polling

Errors, margins and samples: What does the latest poll say? (Originally posted on Yahoo!'s "The Ticket" Blog)

Polls are important. You see a lot of them during a campaign season. The question is, what do they really mean? The quoted margin of errors are large and significant. And, the real error is much larger and more significant than the quote margin