There are two ways to do this.
Option 1: Using a custom blacklist
When creating a study, go to "Audience" and add the custom screening filter named "Custom Blacklist". Participants whose Prolific IDs you enter here won't be eligible to take part in the study.
Please note: You should ideally use the Prolific IDs from the study export or query string. IDs which are manually entered by participants in your study may contain errors, and won't be able to be added to your study's prescreening.
If you have good reasons to believe that a participant is purposefully submitting low quality responses, cheating, spamming, or engaging in any other unacceptable behaviour, please report this back to us by briefly describing the issue and sending the relevant Prolific IDs. We will make sure to block accounts like these.
Option 2: Blocking a previous study
To exclude participants from a previous study from participating again please follow these steps:
- When creating a study, scroll down to the Audience section.
- Add a new custom screening filter and search for "Previous Studies".
- Select the names of the studies whose participants you wish to exclude from taking part in the new study.
- If newly completed studies do not appear on this list, you may need to refresh the page and they should appear.
- Applying the "Previous Studies" screener will also exclude participants who have Returned or Timed Out submissions in your previous study.
Please note: The previous studies you want to block must be in the "Completed" section of your dashboard. These are studies that have been stopped and all participants submissions have been reviewed with payment complete.
If your previous study has not yet been completed but you would like to prevent participants who have participated in it from accessing a new study, please use the 'custom blacklist' option as outlined above.