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 ...

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 ...

A behind-the-scenes blog about research methods at Pew Research Center. For our latest findings, visit pewresearch.org. Pew Research Center conducts surveys all around the world on a variety of topics ...