(The following article is taken from the U.S. Department of State publication, USA Elections in Brief.)
Though not part of the rules and laws governing electoral politics, public opinion polls have become an essential part of the electoral process in recent decades. Many political candidates hire pollsters and take frequent polls. Polling informs political candidates of how well they are being perceived in relation to their competitors, and what issues are uppermost in the minds of the voters. The media – newspapers, television – also conduct opinion polls and report them (along with results of private polls) to give citizens a sense of how their preferences for candidates, issues, and policies stand in relation to the preferences of others.
Fifty years ago, only one or two large organizations dominated public opinion polling. Today, in an era of instant news, the Internet, and 24-hour cable-news channels, numerous sources regularly provide the results of opinion polls.
Polls in History
By now, constant polling of public opinion by private, competent pollsters has become commonplace for individual candidates, as well as for high-level government officials such as the president, who want to know which way the political winds are blowing. However, independent, media-commissioned polls have been more typical throughout U.S. history.
Although the first political poll was conducted in 1824 by the local newspaper in Harrisburg, Pennsylvania, independent polls did not become a staple of media news coverage of political campaigns until the 1930s. By the 1970s, all three major U.S. television network news operations of the day (ABC, CBS, and NBC) were offering their own polls for the presidential races, and thereafter for important state races for governor and for the U.S. Congress.
Modern media polls – such as those conducted in the name of a TV news network and a newspaper partner (e.g., CBS/New York Times, ABC/Washington Post, NBC/Wall St. Journal) – are conducted frequently and can track public opinion about candidates and issues on a weekly, or daily basis. They are well designed to be neutral and independent. Over the decades, independent political polling has offered an objective look at election races, an assessment of each candidate's strengths and weaknesses, and an examination of the demographic groups supporting each candidate. Such independent polling gives reporters and editors the ability to make and report honest assessments of the status of a campaign, and voters a better sense of the political landscape.
Sample Size and Makeup
Sometimes, overnight polls are conducted after a major event such as the president's annual State of the Union Address or a debate between candidates for political office. Often these polls are done in one night for quick publication the next day and feature a sample of only 500 adults nationwide.
While these "overnighters" might offer a fast take on public reaction, some experts believe that a sample of 500 citizens is too small for serious consideration in a nation of more than 300 million people. Many professionals prefer posing questions to at least 1,000 adults to provide a representative sample of the entire population. Even the most thorough polls are open to interpretation, and there are numerous examples of candidates who have risen from relative obscurity to wide popularity, contrary to trends suggested by early polling results.
Early polls can provide a wealth of data well beyond showing which candidates are ahead in the race. They can reveal concern for current issues and portray the public's overall mood. As one pollster has said, "Polls merely add science to what candidates see and what crowds feel – contentment, resentment, anger, frustration, confidence – or even despair." Both private and public polling results, then, help candidates determine the optimum communications message to emphasize, while focusing issues for members of the public.
Exit polls (polls taken by television networks as voters leave their polling places) have been a staple in U.S. elections since the 1970s. They also are arguably the most controversial, because they give TV networks the means to predict election victories based on interviews with people who have just voted. Exit polls achieved particular infamy in the 2000 U.S. presidential election, when they were misused by the television networks to make not one, but two, incorrect projections of the winner who had been selected by voters in Florida. The pressure to get the projection first trumped the pressure to get it right.
However, exit polls, when used properly, can be a vital tool for pollsters, the press, and academics. Above and beyond their questionable use in projecting winners early on election day, they provide experts and political scientists with details of how specific demographic groups have voted and the expressed reasons for their vote.