There are two ways to do this:

Option 1: Exclude participants from other studies

To exclude all participants from selected other studies from participating, please follow these steps:

  1. When creating a study, scroll down to the 'audience' section.
  2. Select 'prescreen participants' and then search for the 'exclude participants from other studies' screener in the search bar. This screener can also be found in the 'participation on Prolific' screener category.
  3. Select the names of the studies whose participants you wish to exclude from taking part in the new study.

Applying the 'exclude participants from other studies' screener will exclude all participants from the selected studies (i.e. approved, rejected, returned, awaiting review and timed out participants).


Option 2: Use a custom blocklist

This can be particularly helpful for researchers running studies across multiple accounts.

  1. When creating a study, scroll down to the 'audience' section.
  2. Select 'prescreen participants' and then search for the 'custom blocklist' screener in the search bar. This screener can also be found in the 'custom screener' category.
  3. Enter the Prolific IDs of the participants you want to prevent from taking part in the study. Participants whose Prolific IDs you enter here won't be eligible to take part in the study.

To generate the custom blocklist, you should ideally obtain the IDs from your Prolific data export or query string rather than using manually entered data. Prolific IDs manually recorded in your survey may contain errors, and invalid IDs will be rejected from the custom blocklist. See here for instructions on how to download your data export.


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