Election polls sample the population to project their actual opinion. They are completely unavoidable if you follow an election. TakePart TV explains how they work.
Political polls sample a small representative population to project the nation’s opinion when it votes. It starts with random calls to landline and cell phones to conduct a short survey. The laws of probability mean that a targeted sample of 1,500 people produces only a 3% margin of error. Even this low margin could mean the race is tied or that either candidate is far ahead. However, previous polls have been quite accurate, having correctly predicted every presidential election since 1980 (except Bush vs. Gore). Some political scientists suggest that polls may be bad for our democracy, because voters who think their candidate is ahead may decide they don’t need to vote, or voters may cast a vote for the underdog out of sympathy.