Estimating your study's completion time

It is important to make your study completion time estimation as accurate as possible. 

In doing this, you will ensure that participants are not initially underpaid for completing your study.
At Prolific, we believe in ethical rewards for participants, our minimum reward per hour is £5/$6.50 USD. You can read more about this in our
minimum payment rate article.
What is the best way to estimate completion time? 
We understand it can be difficult to determine an estimated completion time, we advise researchers to run a small pilot study on Prolific before launching to your full sample (see Running a pilot study), and test it out on your colleagues/friends too. 
How can I fix a study with an underestimated completion time? Participants were underpaid!
We kindly ask you to award bonus payments to any approved submissions, to increase the overall reward to meet the minimum reward per hour requirements.
You can find out how to rectify this issue by paying a bonus to participants
What happens if my study falls below the minimum payment rate?
  • If the study is still active it will be paused by a member of Prolific Support
  • You will be contacted by Prolific and asked to pay the appropriate bonus amount to participants who have completed your study
    • If your study is completed this is all you will have to do :)
  • If you require further participants for your study you will need mark the initial study as “complete”
  • You can then duplicate the initial study and increase the estimated completion time and reward
    • Please note: you will need to add the ‘previous studies’ prescreener to your study to avoid participants taking both versions of the study
    • You can read more about how to do this here
If there is no response to the message we send you within a reasonable amount of time:
  • Your account will be temporarily frozen if we deem this to be necessary
  • If we receive a response indicating that appropriate steps have been taken to resolve the issue, we will reinstate the account

Please note: Prolific uses the median to work out your study's average completion time, so that extreme completion times do not skew the data. 

If you require assistance with this please reach out to Prolific Support ( and we will be happy to help. 
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