About this research This study was designed to measure the impact of bogus respondents on opt-in surveys. It also compares three methods for identifying and removing bogus respondents: 1) the use of trap questions, sometimes called “attention checks,” 2) the Sentry prescreening system proprietary to CloudResearch, and 3) matching respondents to a national voter file. Why did we do this? Pew Research Center does high-quality research to help the public, the media and decision-makers understand important topics. Our methodological research investigates the current challenges facing the polling industry, including past work on the impact of bogus respondents in opt-in surveys . Learn more about Pew Research Center and our methodological research . How did we do this? We fielded a large online opt-in survey Nov. 14-19, 2024, among 11,114 U.S. adult respondents. Respondents who agreed to provide their name and contact information were matched to a registered voter file after the survey concluded.…