If participants are submitting your study with NOCODE or an unexpected completion code, don't worry, this doesn't automatically mean there's a problem with their submission.
What does "NOCODE" mean?
NOCODE means that a participant submitted their study on Prolific without the completion code you provided.
This usually happens because they completed your study manually rather than being automatically redirected back to Prolific with the completion code. In some cases, participants may also enter the wrong completion code by mistake.
Why am I seeing NOCODE on my submissions?
There are two common reasons.
1. The participant completed your study but wasn't redirected back to Prolific
Sometimes participants reach the end of your survey, but something prevents them from being redirected to the Prolific completion URL. Without that redirect, they can't receive the completion code automatically and may submit with NOCODE or enter an incorrect code instead.
If the participant's data shows they completed your study successfully, you should approve and pay the submission as normal. To verify this, you can:
Check your survey data to confirm they completed the study.
Compare their completion time with the expected duration to help confirm they reached the end of the survey.
2. The participant didn't complete the study
A participant may leave your study early or encounter a technical issue that prevents them from finishing. Instead of returning their submission, they may accidentally submit it with NOCODE or an incorrect completion code, causing it to appear in your Awaiting review list.
You can usually identify these cases by:
Checking your survey data for incomplete or missing responses.
Looking for unusually short completion times (for example, only a few seconds).
If this happens, we recommend messaging the participant to ask them to return their submission or to find out whether they experienced a technical issue and would like another opportunity to take part.
If the participant doesn't respond to your return request, please contact our support team.
Participants are using the wrong completion code
If participants are entering an incorrect completion code rather than NOCODE, the cause depends on how widespread the issue is.
Everyone is submitting the same incorrect code
If all (or nearly all) participants are using the same incorrect code, it's likely that:
Your survey redirect is pointing to the wrong completion URL, or
The completion code displayed in your survey is incorrect.
Check that your study is configured correctly, that you're providing the correct completion code, and that the latest version of your survey has been published.
Only one or two participants have the wrong code
If most participants submit with the correct completion code but one or two do not, they may have accidentally copied and pasted the wrong code when submitting manually.
In these cases, it's worth messaging the participant to confirm whether they completed the study successfully and whether they experienced any issues during participation.
Should I approve these submissions?
Yes, as long as you have complete data from the participant and there's no reason to believe the submission isn't genuine (for example, their completion time is consistent with finishing the study), you should approve and pay the submission, even if they submitted with NOCODE or the wrong completion code.
Still unsure?
If you have concerns about a submission with NOCODE or an incorrect completion code, please get in touch with our support team using the button at the bottom right corner of this page. We'll be happy to help you investigate the submission.