On Prolific, participants can only take part in any given study once. This means that if a participant already has a submission in your study then it won't appear in their available studies list and they will not be able to retake it via Prolific.
If for some reason they need to retake your study or repeat their submission, then there are two options for how to allow this:
1. Sending a direct link to your survey to the participant
First, make sure you can find the participant's submission in your submissions list. Then, you can send them a direct link to your study via our internal messaging system (if there is no existing submission then you should follow option 2 below). By direct link, we mean your external study URL.
- Some survey platforms prevent duplicate submissions, so the participant may need to submit a second response using an incognito / private window on their browser.
- If you are recording participant IDs automatically, then the ID will not automatically be uploaded to the survey if the participant is given a direct link. This may result in a participant being unable to access your study. Instead, you will need to ensure that there is an option to manually input their ID in the survey.
Once the participant has completed the study you can approve and pay them using their original submission on Prolific.
2. Creating a duplicate study
In cases where sending a direct link to your study is not feasible, or when no submission already exists for the participant, the best approach is to create a duplicate of your study and use our custom allowlist feature to invite the specific participant(s) to take part. To do this:
Go to your study submissions page, click 'action' > 'duplicate'. This will create a copy of the current study that will share the same URL link and completion code
Find the duplicated study in your 'drafts' tab and open it
In the 'audience' box select 'prescreen participants' and then find the 'custom allowlist' screener
Insert the IDs of the participants you want to take part into the custom allowlist, making sure each ID is separated by a comma
Make sure to remove the automatically included 'exclude participants from previous studies' screener
In the 'study cost' box set 'how many participants are you looking to recruit?' to the required number
'publish' the study
Only the participants that you have added to the custom allowlist will be able to access the study and they should see the study appear on their dashboard. If they cannot see the study on their dashboard, please try sending the participant a message with a direct URL to your study on Prolific. This URL should be of the form:
You can find your unique study ID by opening the study from your account and checking the URL in your browser. For example, if your study ID was '5bbb73d73cdd2a00013fa505' then you would see the URL 'https://app.prolific.co/researcher/studies/5bbb73d73cdd2a00013fa505'.
You will need to slightly amend the URL, removing 'researcher' before sending it to the participant:
As long as participants are eligible for your study, the direct URL should enable them to sign up successfully.
If you have any questions about this feel free to get in touch using the button below.
If these submissions are above and beyond the number originally requested for your study, then you may need to add more money to your account to be able to launch the duplicate study.