Margin of Error (MOE)

The margin of error (MOE) is a statistical concept that is most often associated with polls and pollsters. It serves to quantify the uncertainty associated with sampling in a poll or other survey. In survey research, it is almost never practical to measure the entire population. As a result, pollsters rely on random samples that are intended to be representative of the population. Because polls randomly sample from within a population, there will always be some amount of uncertainty, or variable error (variance), associated with their results. Simply put, if a U.S. pollster were to randomly sample 1,500 adults in a national survey, it is unlikely that these 1,500 people would perfectly reflect the opinions of the 200-plus million adults in the country.

The MOE can ...