Congressional polls are special surveys used to predict how voters will cast their ballots in upcoming elections. Some polls in the United States (US) are strong predictors for election results, though poll results are not a guarantee. Some congressional polls are generic, which means that they ask voters about which party they would vote for if the election were held today. Others are very specific, and cover individual candidates and issues that matter to the voters. There are thousands of surveys about Congress completed every year, and the accuracy and reliability of these polls can vary dramatically.
Almost any person or organization can conduct their own congressional polls. In the US, private groups like the Pew Research Center and Gallup are well-respected for their polls, and their finding are often posted in the media. News organizations also conduct congressional polls, as do colleges and universities. Each political party may conduct polls to help party leaders gauge how well campaign strategies are working, and individual candidates may also canvass voters as part of their campaigns. These polls can also be conducted by special interest groups, lobbies and business organizations.
Typically, polling agencies select a small sample of voters, then ask them to take the poll. Some congressional polls are conducted via phone, while others are completed in person or even by mail. The responses from this small sample of people are taken as a good representation of the opinions of all voters. The accuracy and reliability determines largely on the size of the sample and how randomly it was distributed.
The questions that make up a congressional poll tend to vary based on whether the poll is generic or specific. In a generic poll, polling agents simply ask which party the voter plans to vote for. In specific polls, the questions are about specific issues, such as immigration, education, or health care. Specific polls may also inquire about individual candidates rather than the party as a whole.
People in the US rely on congressional polls to help them predict the results of an election. Some people may be encouraged to vote if they learn that their favorite candidate is not expected to win. Of course, false confidence in poll results can also keep voters at home. Politicians also track these poll results to learn how voters feel about the issues, candidates, and political parties. Poll results can help candidates form more effective campaign strategies, or modify existing strategies to improve their chances of winning.