Many online surveys are conducted using “nonprobability” or “opt-in” samples, which are generally easier and cheaper to conduct. In our latest Methods 101 video, we explore some of the features of nonprobability surveys and how they differ from traditional probability-based polls.

Donald Trump's victory in 2016 and the U.K. "Brexit" decision rattled public confidence in polls. Our new video explains why well-designed polls can be trusted.

In the second video from our Methods 101 series, we’re tackling why question wording is so important in public opinion surveys.

The first video in our "Methods 101" series is about random sampling, a concept that undergirds all probability-based survey research. Here's how it works.

Opinion polls in the U.S. can address the same topic yet reach very different results. There are several reasons this can happen, but we tackle one of the most basic: Did the poll include or exclude the 45% who didn’t vote in November?

Many people wonder: Can polls be trusted? The following essay contains a big-picture review of the state of polling, organized around a number of key areas.

The advantages of these online surveys are obvious – they are fast and relatively inexpensive, and the technology for them is pervasive. But are they accurate?