PollyVote
Encyclopedia
PollyVote is the name of a website and its private prediction model operated by several professors of political science and other academics which, during fall 2008, provided a daily prediction related to the 2008 United States Presidential Election
. The specific outcome it predicts is the Republicans' share of popular two-party vote. The prediction model employed combines different forecasting methods, which its advocates assert should provide it with better predictive ability than some other prediction approaches.
It is comparable to the Iowa Electronic Markets
which, through the information-collecting activities of participants in its betting system, conceivably incorporates all types of information and models incorporated in the PollyVote's system, including the Pollyvote's daily forecast output, which is publicly available.
While the IEM handles new information in complex ways, the PollyVote's method of combination of the several sources of information is simply to take an average of them.
PollyVote also predicted the outcome of the 2006 U.S. House of Representatives Elections, forecasting that the Republicans would lose 23 seats, and thus, their majority in the House. The Republicans lost 30 seats and the House majority in those elections.
. PollyVote applies the principle of combining forecasts to election forecasting and combines forecasts from four components: opinion polls, a prediction market
, expert judgments and quantitative models.
The reasoning behind using multiple indicators is also laid out in a book by Cass Sunstein about PollyVote, titled "Infotopia: How Many Minds Produce Knowledge".
poll average to calculate the Republican share of the two-party vote. Averaging these poll results has been shown to reduce the forecast error in some previous elections.
Furthermore, evidence from the literature shows that early polls are not reliable in predicting election outcomes. In an attempt to react against high uncertainties in early phases of the election campaign, PollyVote damps poll results. It has been shown that damped polls provided more reliable forecasts in some previous elections.
, calculating a 7-day rolling average of the IEM prices. The Iowa Electronic Markets also incorporates the Pollyvote prediction model, through market participants' access to the Pollyvote output.
United States presidential election, 2008
The United States presidential election of 2008 was the 56th quadrennial presidential election. It was held on November 4, 2008. Democrat Barack Obama, then the junior United States Senator from Illinois, defeated Republican John McCain, the senior U.S. Senator from Arizona. Obama received 365...
. The specific outcome it predicts is the Republicans' share of popular two-party vote. The prediction model employed combines different forecasting methods, which its advocates assert should provide it with better predictive ability than some other prediction approaches.
It is comparable to the Iowa Electronic Markets
Iowa Electronic Markets
The Iowa Electronic Markets are a group of real-money prediction markets/futures markets operated by the University of Iowa Tippie College of Business...
which, through the information-collecting activities of participants in its betting system, conceivably incorporates all types of information and models incorporated in the PollyVote's system, including the Pollyvote's daily forecast output, which is publicly available.
While the IEM handles new information in complex ways, the PollyVote's method of combination of the several sources of information is simply to take an average of them.
History
The PollyVote was created in 2004 to demonstrate the power of combining forecasts for U.S. Presidential Elections . It forecast a victory for President Bush over the 8 months that it was making forecasts, and it predicted on the morning of the election that George W. Bush would receive 51.5% of the popular vote, an error of 0.3 percentage points.PollyVote also predicted the outcome of the 2006 U.S. House of Representatives Elections, forecasting that the Republicans would lose 23 seats, and thus, their majority in the House. The Republicans lost 30 seats and the House majority in those elections.
Pollyvote's components
PollyVote currently consists of four components: opinion polls, a prediction market, expert judgments and quantitative models. PollyVote combines forecasts from different components in an attempt to reduce forecast errorForecast error
In statistics, a forecast error is the difference between the actual or real and the predicted or forecast value of a time series or any other phenomenon of interest....
. PollyVote applies the principle of combining forecasts to election forecasting and combines forecasts from four components: opinion polls, a prediction market
Prediction market
Prediction markets are speculative markets created for the purpose of making predictions...
, expert judgments and quantitative models.
The reasoning behind using multiple indicators is also laid out in a book by Cass Sunstein about PollyVote, titled "Infotopia: How Many Minds Produce Knowledge".
Polls
PollyVote uses the RealClearPoliticsRealClearPolitics
RealClearPolitics is a political news and polling data aggregator based in Chicago, Illinois. The site's founders say their goal is to give readers "ideological diversity." They have described themselves as frustrated with what they perceive as anti-conservative, anti-Christian media bias, and...
poll average to calculate the Republican share of the two-party vote. Averaging these poll results has been shown to reduce the forecast error in some previous elections.
Furthermore, evidence from the literature shows that early polls are not reliable in predicting election outcomes. In an attempt to react against high uncertainties in early phases of the election campaign, PollyVote damps poll results. It has been shown that damped polls provided more reliable forecasts in some previous elections.
Prediction markets
Prediction markets have been shown to be more accurate than traditional polls. In its forecast, PollyVote incorporates predictions of the Iowa Electronic MarketsIowa Electronic Markets
The Iowa Electronic Markets are a group of real-money prediction markets/futures markets operated by the University of Iowa Tippie College of Business...
, calculating a 7-day rolling average of the IEM prices. The Iowa Electronic Markets also incorporates the Pollyvote prediction model, through market participants' access to the Pollyvote output.