> 8,620 respondents, but I don't see how they were recruited This is from the PDF listed on the page that you linked: To establish a nationally representa

> 8,620 respondents, but I don't see how they were recruited This is from the PDF listed on the page that you linked: To establish a nationally representative panel, members are recruited on an ongoing basis through address-based probability sampling using data from the US Postal Service’s Delivery Sequence File. Recruited adults in households without internet access are provided a web-enabled device and free internet service. A probability-proportional-to-size procedure was used to select a study-specific sample. All panel members who were aged 18 years and older were eligible for selection. Invitations were sent by e-mail; automatic reminders were delivered to non-respondents by e-mail and telephone beginning 3 days later. A final survey weight variable provided by Ipsos adjusted for the initial probability of selection into KnowledgePanel and for survey-specific nonresponse and over- or under-coverage using design weights with post-stratification raking ratio adjustments. With weighting, the sample is designed to be statistically representative of the noninstitutionalized adult population of the US as reflected in the 2021 March supplement of the Current Population Survey.