🤔 Ask Anything Thread (Newbie Friendly)

Hi @Lotty , based on the screenshots, it looks like a bug to me. If anyone else has encountered this please feel free to chime in

I’m eager to get a token for the HTTP API, but have not received a response to my inquiry to integrations@prolific.co. Is that email address being monitored? Is there some other means of obtaining an API token?

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Hi, I am a graduate student working on my thesis and am considering using Prolific. I am designing a short intervention study and I am curious if, on Prolific, I can have participants sign into my study more than once. For instance, have them sign in once to complete baseline things and the initial intervention, then sign in again for more questions and additional intervention, and then have them sign on a third time to complete final measures. I know this is difficult to do for online research and not all participants will choose to sign in more than once, but I am curious if it is even possible, and if so, how I would go about doing that. Thank you!

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Hi @Taylor_Sloan ,

I think your setup is possible on Prolific. It seems to me that you have to create 3 different studies, corresponding to 3 different measurement times in your research. You can find more information about this design here How do I set up a longitudinal / multi-part study? – Prolific

Long story short, in the first study, you recruit qualified participants into your intervention study and give them the log-in details to access the intervention. In the second and third studies, you will invite the same participants from the first one and use the same survey/experiment link to direct them to your ongoing intervention study. You can encourage their participation in the following studies by giving them bonuses. Instructions on how to set up such a study design are given in the link attached.

That’s it (if I understand your questions correctly :slight_smile: )


That makes sense in terms of my study, I think. Thank you so much! Your help is very appreciated! :grinning:

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Hi Jesse
Welcome to the forums :slight_smile:

I am sorry I did not even know about that email address but I have tagged @Josh who will I think ask the people at integrations to respond to your email. I am afraid I don’t know any other way of getting an API token. But, I also see here that @Jonas_Anso is a software engineer at Prolific who is or was responsible for the API so I have tagging him too. You might also try messaging Jonas.


Hi all,

Small question and I hope it’s not a dumb one. I have got a few RETURNED or TIMED-OUT responses on my survey which is fine but I don’t want to pay them. Now, my problem is I can only select “Approve and pay”. How do I deal with this? Thanks in advance!


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Hello @Sofia_Wolfswinkel! Welcome back!

If you move your cursor on the “Approve All” button you shall see a pop-up note saying “This will only approve submissions which are AWAITING REVIEW”. No need to be worried of the returned or timed-out submissions, since these participants won’t be paid in this way!

Hope this helps!

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Thanks very much for the help, @timtak!


@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.