To better understand the current landscape of commercially available online nonprobability samples, Pew Research Center conducted a study in which an identical questionnaire was administered to nine ...

In addition to point estimates (e.g., % approving of President Barack Obama’s job performance), public opinion polls are often used to determine what factors explain a given attitude or behavior. For ...

Statistics are often estimated from a sample rather than from the entire population. If the inclusion probability of the sample is unknown to the researcher, that is, a nonprobability sample, naively ...

Survey sampling and estimation methods form the cornerstone of modern statistical inference, underpinning research across the social, medical, and natural sciences. At their heart, these methods ...

AP VoteCast is a survey of the American electorate conducted in all 50 states by NORC at the University of Chicago for The Associated Press and Fox News. The survey of an estimated 140,000 registered ...