One quick note: Most polls report margins of error alongside another technical term, “ confidence interval.” In the most rigorous reporting of polls, you might see a sentence near the end that says ...

Hold your breath and make sure you vote, because the result is likely to be a squeaker.

Learn about the confidence interval and why it's a useful metric for business operators, market researchers and investors alike.

And since pollsters generally use a confidence interval of 95 percent, one out of 20 polls will be a statistical outlier – that is, outside the margin of error – just by chance.