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 ...

Our third Methods 101 video explores some of the ways that nonprobability surveys differ from traditional probability-based polls. How do pollsters conduct surveys online and what does that mean for ...

Gudbjartsson and colleagues (June 11 issue) 1 reveal important insights into the transmission of SARS-CoV-2. An aspect of their study that merits further exploration is the positive test results in ...

A study by the universities of Cordoba and Seville develops a method that makes it possible to verify, easily and quickly, whether an olive plantation is traditional, intensive, or super-intensive.