On Election Day, as votes are being tallied and news organizations await results and race projections that can be reported, exit polls are a critical tool providing an early look at who is voting and what’s motivating their choices.
An exit poll is a survey of voters taken as they leave (or exit) their voting location. It’s the only national survey of known voters in the country. It allows news organizations, researchers and voters to understand what’s happening in an election as the results flow in.
Here’s how exit polling works, where they are conducted and how NBC News will be using the exit poll results on election night and the days after.
Who conducts the exit poll?
Since 2003, Edison Research, a firm that specializes in collecting election data, has conducted exit polls on behalf of the National Election Pool. The NEP is a consortium of media networks — ABC, CBS, CNN and NBC News — that pools together resources for one collective vote count and exit poll operation. NBC News independently analyzes and reports on the exit poll results.
What questions are asked?
The exit poll asks voters which candidates they supported for president and in other races. But a number of other attitudinal and issue-based questions are usually included, such as: “What is the most important issue to your vote?” The other key component of an exit poll is asking about a voter’s demographics such as age, gender, race, education. These types of questions help illustrate how different groups voted and what mattered to them, and they are also used to weight the exit poll — that is, to make sure that the exit poll properly reflects the demographic composition of the electorate as well as the election results.
Members of each news organization in the NEP jointly determine in which states the exit polls will be conducted (in addition to the national exit poll survey), and they work together to decide what questions are included on the national and state questionnaires. The exit poll questionnaires include about 25 questions and take around 5 minutes to complete.
How are exit polls conducted?
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The exit poll is then conducted in a random sample of selected polling places across the country and in states with their own exit polls (more on that later). At least one interviewer is assigned to each polling place on Election Day. This year, interviewers will be stationed at 600 polling locations throughout the country, with each of them following local rules about where they can stand in relation to the polling location. The interview is self-administered, meaning the respondent fills out the survey on their own. Then, the interviewers call in their results throughout the day, and the results are reported to news organizations.
What about state exit polls?
In addition to a national exit poll, which captures voters across the country, there are exit polls specifically for states that are pivotal to winning the presidency or include important down-ballot races, such as Senate or governor. This year, NBC News will have coverage of state exit polls in Arizona, Georgia, Florida, Michigan, Nevada, North Carolina, Ohio, Pennsylvania, Texas and Wisconsin. The exit poll will be conducted in 40 balloting locations in each state.
How does the exit poll capture the growing percentage of people voting early or by mail?
The exit poll supplements in-person Election Day interviews by contacting early voters through a telephone poll of people on voter lists in all 50 states, as well as by collecting interviews during early in-person voting periods.
This year, the exit poll is conducting interviews at early in-person voting locations in Georgia, North Carolina, Nevada and Ohio. All voters in a given state, regardless of whether they vote early or on Election Day, are asked the same questions.
Are exit polls anonymous?
Yes. In person, voters are handed a piece of paper and pencil to fill out a paper questionnaire and they answer anonymously. When they are done, they put their folded questionnaire into a box, much like casting a ballot. Interviews conducted by telephone do not retain any personal information about the voter who was interviewed.
How many people are interviewed?
The national exit poll will include approximately 20,000 interviews in total, including in-person on Election Day, in-person during early voting and via telephone to capture other early voters, including those who cast their ballots by mail. For each state exit poll in Arizona, Georgia, Florida, Michigan, Nevada, North Carolina, Ohio, Pennsylvania, Texas and Wisconsin, there will be sample sizes of 1,500 to 2,500 respondents per state.
How do we use exit polls?
The NBC News Decision Desk uses some exit poll data to help project election results. However, the exit poll is primarily used as a reporting tool on election night.
The data gives viewers and readers a look into what issues are motivating voters, how they feel about the country and who they are. It’s the nation’s first look into what the electorate looks like and how voters are feeling about the election, the candidates and their choices.
What data do news organizations report and when?
Participants in the NEP do not report any exit poll results before 5 p.m. ET on Election Day, and no exit poll results that can be indicative of the outcome of a race get reported until after all the polls are scheduled to close in a state. As election night goes on and interviewers on the ground call in more exit poll results, the data is updated and re-weighed in real time.
This story first appeared on NBCNews.com. More from NBC News: