Note: This feature is being rolled out gradually and may not be available to all researchers yet. If you don’t see these options in your account, you can continue using our previous workflow for running longitudinal studies. See How do I set up a longitudinal / multi-part study?
Overview of longitudinal studies on Prolific
A longitudinal study is a study that takes place over multiple waves, where the same participants take part in each wave at different points in time.
On Prolific, longitudinal studies are set up as a sequence of waves within a single project. Each wave is a separate study released over time.
Participants must complete wave 1 and their submission must be approved before they are eligible to take part in wave 2.
How longitudinal studies work on Prolific
Automatic participant eligibility across waves
Prolific manages which participants can take part in each wave.
Participants with approved submissions for Wave 1 become eligible for Wave 2, and so on.
This removes the need for you to manually manage allowlists between waves.
Upfront setup of all waves
You must create all study waves before launching your longitudinal study.
Important: You cannot add new waves after Wave 1 is published
Each wave is setup as a separate study, but some settings apply for all waves within the project - see below
Project-level settings
Some settings are configured once at the project level:
Screeners and participant recruitment
Device requirements
The project details that are seen by participants
These apply across all waves
Participant eligibility rules
In order to access subsequent waves, the participant must:
Complete the previous wave (e.g. complete Wave 1 to access Wave 2, and Wave 2 to access Wave 3 etc.)
Their submission for the previous wave must be approved
If the participant’s submission is rejected or awaiting approval, they will not be eligible to participate in the next wave
Participant limits across waves
Participant numbers must stay the same or decrease across waves, because each new wave can only include participants who completed and were approved in the previous one
Example:
Wave 1: 100
Wave 2: 80 ✅ (only some participants continue)
Wave 2: 120 ❌ (you can’t have more participants than progressed from Wave 1)
This ensures there are enough eligible participants to move forward through each wave
Retention and cost planning tools
The Retention forecast tab helps you plan your longitudinal study by estimating participant drop-off between waves, and total cost across all waves
Using your expected retention rate and study setup, it calculates:
how many participants are likely to drop out between each wave
how many participants you need to recruit in Wave 1 to reach your final target
the total cost of running all waves combined
How to run a longitudinal study on Prolific
Creating a longitudinal study project
Go to Projects
Select + New project
Enter your project name
Select Publish related sequenced studies (longitudinal)
Click Continue
Creating wave 1
Under Wave 1, click Add study
Complete the study setup form as normal, including:
Study link (URL)
Estimated completion time
Reward
Number of participants
Do not add screeners at this stage
Select Save as draft
If you plan to use screeners:
Go to the Project setup and recruitment tab
Add your screeners at the project level
Screeners determine which participants can take part in Wave 1
Creating wave 2 and beyond
Click + Add new wave
Under the new wave, click Add study
Complete the study setup form as normal
Ensure participant numbers are the same or lower than the previous wave
Select Save as draft
Repeat this process for each additional wave
Launching your longitudinal study
Check that:
All waves have been created
All studies are saved as drafts
Add participant-facing project details:
Name
Overview
Additional information
Configure recruitment in the Project setup and recruitment tab
Publishing your study
Click Publish on Wave 1
Review your project details
Tick the agreement box
Click Publish
Once published:
Wave 1 becomes Active
Publishing additional waves
You can publish additional waves at any time, but they must be created prior to Wave 1 being launched
Important:
Participants must complete waves in order
Later waves will only become available after the previous wave is completed and approved
Using the Retention forecast
Set your targets
Enter your Final wave goal
This is the number of participants you want to have in your last wave
Adjust your Target retention rate
This is the percentage of participants you expect to continue from one wave to the next
The default retention rate is set at 80%
This is based on typical attrition rates seen in online longitudinal studies
You can adjust this depending on your study design, timing, and expected participant engagement
View projections
The tool updates automatically as you change your inputs (final wave goal or retention rate)
It shows:
Required recruitment for Wave 1
The number of participants you need to start with in order to reach your final wave goal
This accounts for expected drop-off between waves
Expected drop-off between waves
The number of participants predicted to leave the study at each stage
Based on your selected retention rate
Helps you understand how your sample size decreases over time
Review costs
The tool shows:
Estimated total project cost
The projected total cost of running all waves combined
Based on your current study setup and number of participants required to meet your final wage goal
Cost per wave
The estimated cost for each individual wave
Helps you understand how costs are distributed across your study
Cumulative cost across waves
A running total of costs as participants progress through each wave
Shows how your total spend builds over time
Costs are estimates and may vary depending on actual retention
If more or fewer participants continue between waves, your final cost may be higher or lower than predicted
Wave breakdown table
The table includes:
Study (each wave)
Each wave in your project, shown in order to reflect the study sequence
Amount of participants per wave
Expected participants in each wave based on your final goal and retention rate
Estimated drop-off between waves
Predicted number of participants who leave between each wave
Cost per wave
Estimated cost for each individual wave based on setup and participant numbers
Cumulative cost
Running total cost as participants progress through each wave
Best practice guidance
Retention depends on study design and timing between waves
Shorter gaps and clearer study expectations typically lead to higher retention
Very high retention rates (e.g. 100%) are unlikely
Most longitudinal studies experience some level of participant drop-off
Use conservative retention estimates when planning
Helps ensure you recruit enough participants to meet your final wave goal