In a 2019 Pew test, what share of respondents from online opt-in sources were 'bogus' (fake or careless) interviews?
Answerabout 4% to 7%, depending on the source
Panels recruited by mailing to random addresses had about 1% bogus respondents in each of the two tested.
Source: Pew Research Center, Assessing the Risks to Online Polls From Bogus Respondents (2019) pewresearch.org