I recently recruited a ‘nationally representative’ US sample. Prolific claims that such samples are recruited using cross-stratified demographic quotas so that they approximate the broader US population in terms of age, sex, and ethnicity. I’d like to compare the demographic composition of my sample with that of census survey respondents. But I’m not sure which census year data Prolific is using to determine the quotas. For instance, is it the 2021 American Community Survey? The 2015-2019 5-year ACS estimates? The 2021 Current Population Survey? If anybody has any idea, I’d really appreciate the help. Thanks in advance for your time!