From 
Del.icio.us
Digg
Reddit
Facebook
StumbleUpon
TwitThis
Election '08: Exclusive Interviews, Photo Galleries, Issue Guides and More
Americans use polls to measure everything from the most popular celebrity Halloween costumes (Brangelina, 2007) to, um, our distrust of polls (68 percent of us don't believe the typical poll accurately reflects public opinion). But in an election year, polls and politics are virtually inseparable. Twenty years ago, only a handful of polls tracked presidential races, releasing new results every few weeks; today there are dozens of polls tracking the race on national and state levels.
Polling is one reason running for president is so expensive. This year, presidential candidates had already spent $28.5 million on polling and research by the end of June. What does all this money accomplish? Candidates' polls reflect trends and help them plan campaigns and raise money; media and independent polls drive coverage. Do polls shape voter behavior? Politicians and journalists think so-but how? By drawing voters to likely victors, or by rallying supporters of the underdog? By persuading voters to stay home when they think their choice is a sure winner-or a stone-cold loser? Not even pollsters know.
How can a survey of 1,000 adults accurately represent the views of 230 million? The answer is probability theory. Using a random sample, pollsters can capture a picture of the population as a whole. And the method works. Despite the closeness of the 2004 election, the average of the final major polls fell within about one percentage point of the actual outcome.
Still, polls often produce vastly different results. That's partly due to sample size and margin of error-in other words, chance. Don't obsess over one poll; watch for trends.
Advertisement 
feeds instead
