Election Polling Resources

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Make sense of the latest polls

Make sense of the latest polls and put current results into perspective with these resources.

Understanding & Evaluating Polls

These resources can help you evaluate the quality of a poll and better understand what its results can—and cannot—tell us:

Identifying Likely Voters

One problem election pollsters face is that not all respondents who tell them they plan to vote will do so. Actual turnout (known only after the election) is generally lower than respondents’ self-reports of voting intentions in pre-election polls. So the pollster’s challenge is to try to identify those who will really vote on Election Day and which ones will stay home.

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Sampling and Sub Groups

Sampling Methods for Political Polling

To sample individuals, polling organizations can choose from a wide variety of options. Pollsters generally divide them into two types: those that are based on probability sampling methods and those based on non-probability sampling techniques.

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Automated Polls

 Automated polls – telephone polls that employ a recorded voice in place of a live interviewer go by many names, including robopolls and interactive voice response (IVR) polls.

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Probability-Based Online Panels

Learn how probability-based online panels combine traditional probability sampling methods with online data collection, and how they differ from nonprobability online panels.

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Margin of Sampling Error/Credibility Interval

The margin of sampling error is the price you pay for not talking to everyone in the population you are targeting. It describes the range that the answer likely falls between if we had talked to everyone instead of just a sample. For example, if a statewide survey of adults with a margin of error of plus or minus 3 percentage points finds that 58% of the public approve of the job their governor is doing, we would be confident that the true value would lie somewhere between 55% and 61% if we had surveyed to the whole adult population in the state.

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Measuring Sub-Group Preferences

Journalists need to take into account that when subgroup results are reported, the sampling error margin for those figures is larger than the sampling error for results based on the sample as a whole. Journalists should identify the number of respondents in the subgroup, even for larger groups such as Democrats or men or Hispanics or senior citizens.

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​Nonresponse Effects and Measurement

Measuring Response Rates

Calculating response rates—the number of eligible sample units that cooperate in a survey—has historically been central to survey research in the United States because of the assumption that the larger the proportion of participating sample units, the more accurate the survey estimates. Formulas for calculating rates are now standardized, but the relationship between response rates and survey quality has become much less clear.

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Nonresponse Bias

Nonresponse bias occurs when sampled elements from which data are gathered are different on the measured variables in nonnegligible ways from those that are sampled but from which data are not gathered.

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Special Issues in Election Polling

Herding

“Herding” specifically refers to the possibility that pollsters use existing poll results to help adjust the presentation of their own poll results. “Herding” strategies can range from making statistical adjustments to ensure that the released results appear similar to existing polls to deciding whether or not to release the poll depending on how the results compare to existing polls.

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A Primer on Pre-Election Polls: Or Why Different Election Polls Sometimes Have Different Results

Election polls are a special breed among public opinion surveys. They call for more judgments—the art rather than the science of the craft—on the part of the pollster than other types of polls. And this brings into play a host of other reasons why the estimates of well-established and well done pre-election polls may differ from one another, even when these polls are conducted at a similar point in time.

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What is a “Push” Poll

This statement from AAPOR explains how to tell the difference between fraudulent political polls—commonly referred to as “push polls”—and legitimate polling, including message testing. AAPOR condemns political telemarketing under the guise of research and is committed to providing information that explains what this unethical campaign practice is and what you can do about it.

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Poll Aggregators

At the simplest level, a poll aggregator is an individual or organization that brings together many poll results from a number of different sources. Generally, poll aggregators compile results of polls through a certain time period, using national or state polls. But not all aggregators are alike.

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For Students and Teachers

The Poll Picture

Public opinion polls can give insight into people’s priorities and opinions, and give candidates and the media a sense of the whole picture. Use this infographic to show how public opinion polling works, from pollster to prediction! Students will engage with the concept of sampling and gain a better understanding of the purpose of public opinion polls.

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Roper Center Learning Tools

Explore these resources from the Roper Center for learning about polling and public opinion research, including polling fundamentals, classroom materials, tutorials, and other educational tools.

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