Learn how representative samples and random samples differ and why combining them minimizes sampling bias for accurate data.

The first video in Pew Research Center’s Methods 101 series helps explain random sampling – a concept that lies at the heart of all probability-based survey research – and why it’s important. Fresh ...

Discover how to determine the ideal percentage of a population for a representative sample to ensure accurate data analysis with minimal sampling error.

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 ...