Political forecasting
Encyclopedia
Political forecasting
aims at predicting the outcome of elections. Models include:
are an integral part of political forecasting. However, incorporating poll results into political forecasting models can cause problems in predicting the outcome of elections. There are a few ways in which inaccurate election forecasts can be avoided.
poll average.
s like the Iowa Electronic Markets
provide highly accurate forecasts of election outcomes. Comparing market forecasts with 964 election polls for the five US presidential elections from 1988 to 2004, Berg et al. (2008) showed that the IEM outperformed the polls 74% of the time. However, damped polls have been shown to outperform prediction markets. Comparing damped polls to forecasts of the Iowa Electronic Markets, Erikson and Wlezien (2008) showed that the damped polls outperformed both the winner-take-all and the vote-share markets.
of past elections to forecast the percent of the two-party vote going to the incumbent party candidate in the next election.
Most models consist of between two and seven variables and are estimated over anywhere between scarcely over a dozen elections to close to twice as many. (By contrast, historian Alan Lichtman uses 13 “Keys” to predict whether the incumbents will be reelected.)
A common denominator across most quantitative models is at least one measure of economic conditions, although no two employ the same metrics. Also, most models include at least one public opinion variable, a trial heat poll or a presidential approval rating, although here again there is no unanimity on indicators.
Forecasting
Forecasting is the process of making statements about events whose actual outcomes have not yet been observed. A commonplace example might be estimation for some variable of interest at some specified future date. Prediction is a similar, but more general term...
aims at predicting the outcome of elections. Models include:
Opinion polls
PollsOpinion poll
An opinion poll, sometimes simply referred to as a poll is a survey of public opinion from a particular sample. Opinion polls are usually designed to represent the opinions of a population by conducting a series of questions and then extrapolating generalities in ratio or within confidence...
are an integral part of political forecasting. However, incorporating poll results into political forecasting models can cause problems in predicting the outcome of elections. There are a few ways in which inaccurate election forecasts can be avoided.
Averaging polls
It is well documented that combining poll data reduces the forecasting error of polls. Political forecasting models often include averaged poll results, such as 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.
Poll damping
Poll Damping is a method of discounting flawed indicators of public opinion when creating a forecasting model. Often, polls early in the campaign are poor indicators of the future choices of voters. By weighting the poll results from days closer to an election to a greater degree than previous polls, a more accurate prediction is established. Campbell (1996) demonstrates the power of poll damping in political forecasting.Markets
Prediction MarketPrediction market
Prediction markets are speculative markets created for the purpose of making predictions...
s like 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...
provide highly accurate forecasts of election outcomes. Comparing market forecasts with 964 election polls for the five US presidential elections from 1988 to 2004, Berg et al. (2008) showed that the IEM outperformed the polls 74% of the time. However, damped polls have been shown to outperform prediction markets. Comparing damped polls to forecasts of the Iowa Electronic Markets, Erikson and Wlezien (2008) showed that the damped polls outperformed both the winner-take-all and the vote-share markets.
Regression models
Political scientists and economists have employed regression modelsRegression analysis
In statistics, regression analysis includes many techniques for modeling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables...
of past elections to forecast the percent of the two-party vote going to the incumbent party candidate in the next election.
Most models consist of between two and seven variables and are estimated over anywhere between scarcely over a dozen elections to close to twice as many. (By contrast, historian Alan Lichtman uses 13 “Keys” to predict whether the incumbents will be reelected.)
A common denominator across most quantitative models is at least one measure of economic conditions, although no two employ the same metrics. Also, most models include at least one public opinion variable, a trial heat poll or a presidential approval rating, although here again there is no unanimity on indicators.