Recruiting on Prolific

Overview

The experiment is live. This lesson covers the Prolific side: creating a study, configuring screening criteria, setting payment, writing the study description, and launching. By the end, real participants will be able to find your study, consent, complete it, and receive payment automatically.

Creating the Study

1. Log into prolific.com with the account you created in the Prerequisites lesson.
2. From your dashboard, click New Study.
3. Choose External Study Link. Prolific also offers other study types (external survey tools, interviews); this experiment is a external online study since the entire task lives on your own Vercel URL.

You'll land on a setup form with several sections. Work through them top to bottom.

Study Name and Description

Participants see this before deciding whether to take your study, so it needs to be accurate without giving away the manipulation. This is not the informed consent document — that's the detailed consent page you built in an earlier lesson, which participants see after starting the study. This is just the pitch on Prolific's study list, so keep it neutral and avoid words like "resurgence," "reinforcement," or "extinction" that would tip off the phase structure before consent.

Prolific asks for two different names. The internal name is only ever visible to you, in your own Prolific dashboard, so it's fine (and useful) to be specific about what the study actually is. The study name is what participants see, so it stays neutral.

Paste these directly into the corresponding fields, then adjust the bracketed duration in the description to match your actual PHASE_MINS settings:

Internal Study Name:
Resurgence Task - Pilot 1

Study Name:
Online Decision-Making Task

Description:
In this short online study, you will complete a computer-based task that
involves clicking on moving on-screen shapes to earn points, followed by a
few brief questions about yourself. The study takes approximately
6 minutes to complete.

Adding the Study URL

Paste your Vercel production URL (the one from the Deploying to Vercel lesson, e.g. https://your-project-name.vercel.app) into the Study URL field.

Because this experiment collects the Prolific ID with a manual text field on your own entry page rather than through URL parameters, you don't need to add any placeholder variables to the link. The plain URL is enough — participants will type their ID in themselves once they land on it.

Completion Codes

Further down the setup form, Prolific asks how you'll confirm participants finished. Select "I'll redirect them using a URL." Prolific generates a completion URL for this specific study, which looks like:

https://app.prolific.com/submissions/complete?cc=XXXXXXXX

This is the value the debrief page needs, referenced back in the Debrief Page lesson as PROLIFIC_COMPLETION_URL. Copy it now:

1. Add it to your local .env file:

   PROLIFIC_COMPLETION_URL="https://app.prolific.com/submissions/complete?cc=XXXXXXXX"
   

2. Add the same value in your Vercel project under Settings → Environment Variables.

3. Trigger a redeploy (push a commit, or click Redeploy in the Vercel dashboard) so the live app picks up the new value.

Until you do this, the debrief page's "Return to Prolific" button falls back to the generic Prolific homepage, so nothing breaks — participants just won't be routed back correctly to confirm their submission, so it's worth doing before you publish.

Screening Criteria

Prolific's Screening section lets you restrict who can see and take your study, separate from anything you ask in your own demographics page. Common filters for a study like this one:

Only add filters that matter for your task. Every filter narrows your eligible pool, which can slow recruitment. If device type doesn't actually affect your task, leave it open.

Setting Payment

Prolific requires a minimum hourly rate (check the current minimum on Prolific's own pricing page, since it changes over time). Estimate your study's total duration generously: informed consent, demographics, instructions and the comprehension check, all three task phases, and the debrief. Multiply your estimated minutes by the minimum hourly rate to get a baseline reward, then round up.

Prolific will show you the effective hourly rate as you adjust the reward amount. Studies that pay well below what similar studies offer tend to sit unrecruited or get completed carelessly. If data quality matters (and for a timed, phase-based task like this one, it does), it's worth paying at or above the Prolific average rather than the bare minimum.

You'll also set the number of participants here. Consider running a small pilot batch (5–10 participants) before committing to your full sample, so you can catch problems while the cost of a mistake is still small.

Publishing

Once every section is filled in, Prolific shows a Review screen summarizing the study, cost, and audience size. Check it over, then click Publish.

Your study is now visible to eligible participants on Prolific and will start recruiting immediately (or at your scheduled start time, if you set one).

Monitoring While It Runs

While the study is live:

• Watch the Submissions tab on Prolific as participants complete the study. Each submission needs to be manually approved (releasing payment) or, in rare cases, rejected with a reason, within Prolific's review window.
• Cross-check against your own data. Open Prisma Studio with npm run db:studio and confirm taskCompleted is true for participants who submitted on Prolific. A submission with no matching completed record is worth investigating before you approve payment.
• If you ran a pilot batch first, review the block-by-block data before opening up the rest of your sample. This is your chance to catch a misconfigured parameter (say, a reward FR schedule that's harder than intended) before it affects your full dataset.

Make It Your Own

There's no code to write in this lesson, but a few decisions are worth revisiting before you publish for real:

• Re-read your study description and consent page together — make sure neither one gives away the phase structure the debrief later explains.
• Confirm your screening criteria actually match your study's inclusion/ exclusion criteria from your IRB protocol, if you have one.
• Decide your pilot size and full sample size ahead of time, so you're not making that call mid-recruitment.