After my post the other day on tracking public opinion with biased polls, someone pointed me to this 2011 article by David Yeager, Jon Krosnick, LinChiat Chang, Harold Javitz, Matthew Levendusky, ...

One possible explanation for the variability in estimates across the different nonprobability samples is the range of methods that online sample vendors employ. They differ on recruitment, weighting ...

Statistics are often estimated from a sample rather than from the entire population. If the inclusion probability of the sample is unknown to the researcher, that is, a nonprobability sample, naively ...