In a recent research article (https://psyarxiv.com/jq589/), we reported on the size of the MTurk worker pool. Using observed participation rates from the TurkPrime database, we found that over each of the last three years there have been approximately eighty to eighty-five thousand US workers active on MTurk each year (Figure 1). What these numbers do not illustrate is how often new workers join the platform—a number that is important for researchers who want to sample naive participants.