Polls are a snapshot, and other helpful things to remember during the midterm elections

With Election Day just a few weeks away — and millions of votes already cast — midterm polls are everywhere. While polling can be a helpful tool to understand the electorate, it's not a crystal ball.

<img src='https://npr.brightspotcdn.com/dims3/default/strip/false/crop/5209x3473+0+0/resize/5209x3473!/?url=http%3A%2F%2Fnpr-brightspot.s3.amazonaws.com%2Fbb%2F28%2Fc3b5a6eb4ed2b807f1d8621e82c6%2Fgettyimages-2295286708-1.jpg' alt='Residents line up to cast their early-voting ballots in Arlington, Va., on Sept. 18, the first day of early voting in the state.'/><p>With Election Day just a few weeks away — and millions of votes already cast — midterm polls are everywhere. While polling can be a helpful tool to understand the electorate, it's not a crystal ball.</p><p>(Image credit: Tom Brenner)</p><img src='https://media.npr.org/include/images/tracking/npr-rss-pixel.png?story=nx-s1-5996916' />