🤔 Ask Anything Thread (Newbie Friendly)

@Jonas_Anso Can you point me in the right direction about getting an API key? I found this in the API docs, but I haven’t seen a response to the email I sent:

The Prolific API uses API token to authenticate requests. You can request an API token by contacting us on integrations@prolific.co with your name and email that you use for your Prolific account.

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Hi Prolific team,
I noticed that recently the number of eligible participants has dropped quite a bit. Just wondering what’s happened? In previous studies just 3 or 4 weeks ago max, I used the same prescreeners, and I remember back then I had a participant pool of about 85K out of 305K. Today, it’s only about 78K out of 250K? So many people who deleted their accounts within such a short time?


Does Prolific support Ecological Momentary Assessment practices?

Hi Thomas,

Welcome back.

My guess is that it is because Prolific went viral on Tiktok in late August
The thousands and thousands of new participants remained active for about a month, checking out the site for new studies but then stopped coming and now three months later, the number of active participants in the last 90 days is showing the drop off of the Tiktok surge.

I may be wrong about this. If I am right it would mean that while the numbers have dropped, even inactive participants are I think emailed and called back to the site if the active participants do not fill your study places. I am still not quite sure about how emailing works (sorry about that).

Does that make sense, or is there another explanation?


Welcome to the forums Myles!

I did not know what EMAs were until I Googled them.

Please see

Two issues are

  1. The time taken to do a study is normally presumed to be time spent on the study so if you attempted to specify a long term period, you’d be asked to pay the participants for all the time that they were being ecologically observed.
  2. There is a maximum time which is less than the sort of long term periods that you are looking at.

So you can either set up the study initially for a short period of time, making payment appropriate to the whole longitudinal period, but only approve payment at the end of the longer span as recommended in the blog post above.

Or if you had an initial study asking whatever questions needed to be asked initially, if only to explain the study and obtain acceptance. Then you could promise and later pay participants for their participation in the long term study using a bonus paid through the system.

This circumvents Prolific’s monitoring of the amount being paid and is therefore non optimal but it is one of the methods accepted for interviews and focus groups.

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Hi, all. A couple minutes ago I posted my question in a different part of the Prolific forums, but I think my question makes more sense here.

I’m wondering whether y’all can give me some thoughts on how to decrease my rate of no-shows for group video interviews (done via Zoom).

My current design is as follows: In Study 1, I have participants (screened for webcam-use, and consent to do video interviews, etc.) indicate their availability for pre-set appointment times for the upcoming two weeks (this is done via Qualtrics survey). Afterwards, I send them a message via Prolific to announce the appointment time I have chosen for them (based on when most respondents are available). Then, I publish Study 2 (with Custom Allowlist) for which the study URL is the actual Zoom URL. Toward the end of our group Zoom session, I send everyone (via the Zoom chat box) a URL to another Qualtrics survey which automatically routes them to the Prolific Study Complete page when they complete that survey.

However, I’m running into the issue of up to 30% of participants not showing up for their session. (I am forming groups of 3; if I schedule 15 participants, I should have 5 groups. But if one person doesn’t show up, I have to send two people home with a prorated payment sent via the “Bonus” feature after they Return the study in Prolific.)

Currently, the day after they complete Study 1, I send an announcement of their appointment date/time and I ask them to confirm by replying to my message. I also send a reminder message (1) the day before their session, (2) the morning of their session, and (3) one hour before their session (all messages via Prolific). Also, I publish Study 2 immediately after announcing it (the day after Study 1). That way, Study 2 stays visible in their queue as a visual reminder (the first line of the description of Study 2 is an instruction to not start the study until their appointment time).

Edit: The sessions are 45-minutes long, held in the evenings, and I’m paying $9 (equivalent to $12 per hour).


Hi @Moses_Rivera,

Have you tried to make use of delayed payment? If you haven’t, I think it could be of great help. You have 21 days to make a payment decision when you receive a submission. Since your study’s length is within this timeframe, you could clearly communicate to participants that payments will be made only when they have completed all parts of the projects. When participants know that their income depends on their engagement in the entire project, they will show more enthusiasm and cooperation.

Hey @jessesnyder, welcome to the community!

Apologies for the delay in getting back to you, the team is quite busy at the moment. @Elaine, our head of integrations, will send you an email as soon as possible :slight_smile:

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Hi Tim. Thanks for your answer. I suspected that this would be the case. But is your answer also an official answer from Prolific that explains this large reduction of the participant pool? Cheers, Thomas

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Thanks, @Josh and @Elaine. Looking forward to hearing more.

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Thanks for the idea, Chloe! I hadn’t yet thought of that, and I think it would definitely help.

Hello and thanks in advance for the help. I believe I found this answer on the website, but would love your confirmation.

How do leftover funds from a Completed project get handled? Once a study is Completed, do the remaining funds get returned to the overall balance, which can then get reallocated as needed?


Hey @Thomas_Dudek, if you let me know what prescreeners you were using, we can try to narrow down the reasons :slight_smile:

@Chloe_Nguyen , on second thought, wouldn’t this violate Prolific’s terms which call for all eligible participants to be paid, based on pre-screening? In other words, if I withhold the payment for the screener until they complete Study 2, isn’t that essentially withholding compensation via a custom screener?

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Hi, all. The “Duplicate” option is greyed out for one of my completed studies. Why is that? And how can I now duplicate it? (see screenshot)


Yes, leftover funds are returned to the balance, which I have reallocated as needed, in my experience.


Hi Moses

I was just going to ask exactly the same question! My duplicate button is greyed out too. I am sorry I don’t have an answer either. It is nice to know I am not the only one though. Perhaps something is going on at Prolific, preventing duplication, right now!?

I have rejected one submission. Perhaps until that dispute settles I am not allowed to Duplicate. But your study is completed so that is probably not the reason.

I opened the old study in a separate window, and created a new study in another window, then copied all the details to the new study, set up the same prescreeners and added the extra prescreener (which would have been added automatically had I been able to duplicate) to exclude participants from the study that I would have liked to have been able to duplicate. It took less than ten minutes but, if anyone knows the reason why our “Duplicate” is greyed out, please let us know.


Hi @Moses_Rivera,

That’s a good point. However, Prolific actually has mentioned this in their article so I think we’re safe to go.

Can I delay payment until all parts of the study are completed?

If your study consists of multiple waves you can wait until the final wave is complete before paying each wave provided that the waves are within 21 days. To do this, you would leave the submissions from the earlier studies as ‘awaiting review’ until you are ready to approve them. Submissions will be automatically approved after 21 days if they are still awaiting review at this point.

Please specify that payments will be delayed until completion of all parts in your study description, so that participants are fully aware of the requirements in advance of agreeing to take part.

If the waves are over a longer period all participants from each stage will need to be approved within 21 days.

Hi all,

I’m afraid I have a question again. I’m conducting a multi-part (i.e. two part) study and realised a little too late that I needed more balance to conduct the second part. Now, I topped up my balance by transferring money (from Dutch bank to Prolific) and unfortunately, my balance is still not topped up yet. I am aware that this may indeed take 5 workdays (it has been three now), but I am a bit stressed as the second part of the study cannot be further delayed then Wednesday (tomorrow).

So my question, I believe when I top up my account by credit card, the money is transferred directly on my account. So I am considering topping up again the same amount of money by using a credit card hoping that it will directly be on my Prolific balance. Is this allowed? Because there will be quite some money that I’ll have to refund after the study. And is it indeed a safe bet that the money will be on my account directly if I use my creditcard?


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Hey @Sofia_Wolfswinkel, hope you’re well!

Is this allowed? Because there will be quite some money that I’ll have to refund after the study

Yep, this shouldn’t be a problem. Just send a request to our support team, and they’ll process the refund :slight_smile:

And is it indeed a safe bet that the money will be on my account directly if I use my creditcard?

A very safe bet

Lmk if you have any other questions!

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