I am new to the platform and am going to launch several studies as well as a pre-screener study before launching the main studies. As it greatly impacts the amount paid to the participants, I am curious how Prolific records the completion time of a study. What is considered as the start and end times?
Hopefully someone who actually knows will provide a better answer. I am guessing that the start and finish times are from the time they click the link to your study from the description until they submit a completion code. My methods are pretty much fixed in time, and should only vary by about 5 minutes, and I record the start and finish times within the method itself. Most of the time they are pretty close- for instance if my game runs 25 minutes the completion times will usually be between 26 and 35 minutes, but sometimes there are outliers who take an hour or more. Since the task itself cannot run that long, I’m guessing that the time to complete depends on when they submit the code.
There’s a timer that begins when a participant “starts” the study. They can reserve a place before they “start”. Participants can only reserve a place for a limited time before their spot becomes open again. One a participant “starts” the study, in addition to recording the time to completion, there is a maximum allowed time that is generally much longer than the expected time.
The timer ends when a participant indicates that they have completed the study. The “time per hour” is/should be calculated for the median participant (which means that of course, there will be a few exceptional participants who take a long time, but they won’t influence the statistic substantively). If you make sure you tell the participants on the introduction screen to complete the study immediately, there’s no reason to think that participants would lollygag (especially for a brief study).