As the costs and nonresponse rates of traditional, probability-based surveys seem to grow each year, the advantages of online surveys are obvious – they are fast and cheap, and the technology is pervasive. There is, however, one fundamental problem: There is no comprehensive sampling frame for the internet, no way to draw a national sample for which virtually everyone has a chance of being selected.
The absence of such a frame has led to lingering concerns about whether the fraction of the population covered by nonprobability approaches can be made to look representative of the entire population. …
To better understand the current landscape of commercially available online nonprobability samples, Pew Research Center conducted a study in which an identical 56-item questionnaire was administered to nine samples supplied by eight different vendors. CONT.
Pew
