How Do Older Adults Recruited Using MTurk Differ From Those in a National Probability Sample?

A growing number of studies within the field of gerontology have included samples recruited from Amazon's Mechanical Turk (MTurk), an online crowdsourcing portal. While some research has examined how younger adult participants recruited through other means may differ from those recruited using MTurk, little work has addressed this question with older adults specifically. In the present study, we examined how older adults recruited via MTurk might differ from those recruited via a national probability sample, the Health and Retirement Study (HRS), on a battery of outcomes related to health and cognition. Using a Latin-square design, we examined the relationship between recruitment time, remuneration amount, and measures of cognitive functioning. We found substantial differences between our MTurk sample and the participants within the HRS, most notably within measures of verbal fluency and analogical reasoning. Additionally, remuneration amount was related to differences in time to complete recruitment, particularly at the lowest remuneration level, where recruitment completion required between 138 and 485 additional hours. While the general consensus has been that MTurk samples are a reasonable proxy for the larger population, this work suggests that researchers should be wary of overgeneralizing research conducted with older adults recruited through this portal.