As MTurk was not designed for psychological research, it cannot be expected to provide the experimental control that psychologists typically exercise when recruiting participants for laboratory studies. In particular, MTurk lacks:
(I) The ability to exclude participants that have already participated in related studies.
(II) The ability to prevent study previews.
(III) The ability to verify participants’ completion of a study.
TurkGate, or Grouping and Access Tools for External surveys (for use with Amazon Mechanical Turk), gives researchers an easy-to-use web application for providing such control when using MTurk with externally hosted studies (e.g., Qualtrics surveys).