To better understand the current landscape of commercially available online nonprobability samples, Pew Research Center conducted a study in which an identical questionnaire was administered to nine ...

In addition to point estimates (e.g., % approving of President Barack Obama’s job performance), public opinion polls are often used to determine what factors explain a given attitude or behavior. For ...

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 ...

With a population of over 40 million users worldwide, a number doubling every year, the internet has become a medium with distinct business opportunities. To academic and commercial researchers, the ...

1. Distinguish between probability and non-probability sampling and discuss the advantages and disadvantages of each. If you can not specify the probability that any given individual will be in the ...

Non-probability samples provide a challenging source of information for official statistics, because the data generating mechanism is unknown. Making inference from such samples therefore requires a ...