She has conducted in-depth research on social and economic ... systematic sampling may lead to biased results. For example, if the sampling frame only includes individuals from certain demographic ...

Proprietary research is not exempted. Methodologically, in all or nearly all cases, ABC News requires a probability-based sample, with high levels of coverage of a credible sampling frame.

The survey analysis is drawn from a national cross-sectional survey conducted for Pew Research Center by Westat ... in combination with other races or Hispanic identity. The main sample frame of the ...

In a random sample, every element of a population belongs to the sampling frame and... We’re long-term subscribers to WARC and it’s a tool we use extensively. We use it to source case studies and best ...