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 ...

verybody has a favorite color and season—preferences that seem innate, always defying reason. Auditors are no different when it comes to haphazard sampling, a process in which—ideally—they choose ...

The study of hard-to-reach populations presents significant challenges. Typically, a sampling frame is not available, and population members are difficult to identify or recruit from broader sampling ...

This is a preview. Log in through your library . Abstract Background: Estimating the sizes of populations at highest risk for HIV is essential for developing and monitoring effective HIV prevention ...

Research published this month found that even in pristine, untouched areas, insect populations are still on the decline.