Replication Data for: Mechanical Turk and the \"Don't Know\" Option

Luskin and Bullock’s (2011) randomized experiment on live-interview respondents found no evidence that ANES or TESS respondents hide knowledge behind the “don’t know” option (DK). We successfully replicate their finding using two online platforms, the Cooperative Congressional Election Study (CCES) and Google Surveys (GS). However, we obtain different results on Amazon’s Mechanical Turk (MTurk). We attribute this difference to MTurkers’ experience with attention checks and other quality control mechanisms, which condition them to avoid errors. This conditioning leads MTurkers to hide knowledge behind DK in ways not observed on other platforms. Researchers conducting political knowledge experiments on MTurk or piloting surveys on MTurk should take note of these differences.