Many people have asked: "Which polls do you use?" To be as transparent as possible, all the raw polling data used is available for viewing and downloading as described below.
A different, but relevant question is: "Do you use every poll by every pollster?" The answer is no. By far, the vast majority of pollsters are consultants who are hired by candidates and parties to help them win elections. Many of them are quite good at keeping their eye on the ball--winning. To them, being honest is a tool to be used selectively, when it helps their overall goal. In general, these companies will release numbers when they make their candidate look good but if the numbers don't look good, they won't say anything. In some cases, they have been known fudge the numbers or even make them up out of thin air. Furthermore, almost none of them publish their questions, methodology, or crosstabs making independent analysis impossible, whereas legitimate pollsters frequently publish this information (sometimes only to subscribers though). None of their polls are used on this site. Only polls from neutral pollsters, who are generally hired by the media are used.
There are two borderline cases: Rasmussen Reports and Public Policy Polling. Rasmussen Reports is owned by Scott Rasmussen, who makes no bones about being a staunch Republican and who works for Fox News. He pioneered robopolling (automated calls made by a computer) and can thus run polls very quickly. While no one doubts that he actually runs the polls he says he does, the demographic models he uses to weight his data have been criticized as being skewed towards the Republicans. Public Policy Polling frequently works for left-of-center organizations like some unions but is not a campaign-strategy consultant-type company trying to win an election. It also uses robopolling. Nate Silver, a professional statistician now writing a blog for the New York Times, has analyzed the polling data from past elections and concluded that Rasmussen's data was biased towards the Republicans by about 4%. Interestingly enough, PPP's data is also skewed toward the Republicans, but only by a tiny amount, probably due to random fluctuations. In this cycle, Rasmussen has the misfortune that PPP is running many polls, often of the same states as PPP, so comparisons will be much easier this time as there is a lot of data out there to look at. We will be keeping an eye on this, but for the time being, both are included in the database.
Viewing the Polling Data
If you just want to view nicely formatted and color-coded polling data (rather than downloading it for use in Excel or Open office), click on this link.
Downloading the Polling Data
The raw (unformatted) polling data is available for the Senate races here:
Every poll occupies one line.
The flat ASCII text fields are:
State Dem-% GOP-% Ind-% Starting-month Starting-day Ending-month Ending-day Pollster
The .csv files are formatted with the following comma-separated fields:
Day, Poll-length, State/CD, (empty), Dem-%, GOP-%, Ind-%, Ending-date, (7 empty fields), Pollster-poll-length
Polling Data in Graphical Form
If you prefer your data in graphical form, here it is.