A behind-the-scenes blog about research methods at Pew Research Center. For our latest findings, visit pewresearch.org. Ask a survey methodologist to explain random sampling, or how non-probability ...

International surveys provide information about how people in different countries are thinking about issues, but polling in different parts of the world can be very challenging because what works in ...

Learn the distinctions between simple and stratified random sampling. Understand how researchers use these methods to accurately represent data populations.

Sampling is the process of creating a small unbiased population to be used in a test or experiment. The sample removes the impractical idea of surveying everyone in a market or a population. Random ...

Ali Hussain has a background that consists of a career in finance with large financial institutions and in journalism covering business. Vikki Velasquez is a researcher and writer who has managed, ...