90% of prolific workers "returned" for OSWEB experiment
I had my first experience with deploying a study online through prolific. The experiment is hosted on https://jatos.cogsci.nl/
I aimed for 8 participants as a pilot dataset, and set the required sample size to 8 on prolific. I used the "general multiple worker" option in Jatos, and there too I set the maximum number of links to 8.
Once the experiment was deployed many workers "started", and most got "returned". When they got back to me about this, they told me that they received a message that the experiment was already full once they clicked on the link.
I then thought this might have been due to the maximum number of 8 links set in jatos, and I removed this maximum. The problem persisted with 6 out of 10 participants still receiving the same "study is full" message.
All in all, about 80 people started my experiment through prolific, of whom 90% got the "study is full" message. Looking back at the timeline of when people started on prolific, it seemed unlikely that the study could already have been full when participants "returned" after getting the "study is full" message, see below: