"Here at Pew Research Center, we are often asked about how we conduct our research. We work hard to make our methodologies transparent and understandable, but we also know that survey mode effects and data weighting aren’t on everyone’s short list of water-cooler conversation topics.https://www.pewresearch.org/fact-tank/2017/05/12/methods-101-random-sampling/
That’s why we’re launching Methods 101, a new occasional video series dedicated to explaining and educating the public about the basic methods we use to conduct our survey research. We hope this effort will make survey methods more accessible, even if you’re not a statistician or pollster. We also hope it will help give our audience the confidence to be savvy consumers of all polls.
Our first video is about random sampling, a concept that undergirds all probability-based survey research. The video explains what it means and why it’s important. We hope you’ll find it useful."