And why they sometimes surprise us in presidential elections. Support our work. Become a Vox Member today: http://www.vox.com/memberships Subscribe to our channel and turn on notifications (????) so you don't miss any videos: http://goo.gl/0bsAjO Polls seem to be dominating the news cycle this US election season, and they’re giving people cause to celebrate or despair depending on how their preferred candidate is faring in them. But if you understand what polls are actually capable of telling you, it might dispel any desire you have for them to predict whether Kamala Harris or Donald Trump will be the next president. We interviewed pollsters about their processes and explained the basics of how they turn small surveys into a way to measure the entirety of a voting population. No matter what measures pollsters take to make their samples as representative as possible, there’s a limit to how precise they can be. And, sometimes, those same measures can make the poll numbers go awry. S