Last December, a joint survey by The Economist and the polling organization YouGov claimed to reveal a striking antisemitic streak among America’s youth. The Economist/YouGov poll was a so-called opt-in poll, in which pollsters often pay people they’ve recruited online to take surveys. According to a recent analysis from the nonprofit Pew Research Center, such polls are plagued by “bogus respondents” who answer questions disingenuously for fun, or to get through the survey as quickly as possible to earn their reward.