Pew Research Center designed this study to assess the current state of online survey sampling methods – both probability-based and opt-in – and determine their accuracy on general population estimates ...

Historically, public opinion surveys have relied on the ability to adjust their datasets using a core set of demographics – sex, age, race and ethnicity, educational attainment, and geographic region ...

The CAGE questionnaire is a series of four questions that doctors can use to check for signs of possible alcohol dependency. The questions are designed to be less obtrusive than directly asking ...