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How to Schedule Tasks + EMAs in Labfront (Fixed, Randomized, or Semi-Randomized)

Labfront supports flexible task scheduling, allowing researchers to control when and how often tasks, such as EMAs, are delivered, including fixed, randomized, and semi-randomized timing.


This article will cover:


Adding a Task Schedule

When creating a task, you will be prompted to Add a Schedule.


One-Time vs. Recurring

You can choose whether a task occurs once or repeats over time:

  • One-Time Only: The task occurs once on a specific day relative to a participant’s start date.
    • e.g., Onboarding questionnaire on Day 2 of the study
  • Recurring: The task repeats on a regular schedule, following the specified recurrence pattern.
    • e.g., Workday stress check-in Monday to Friday at 4:00 PM 


Recurrence Patterns

For recurring tasks, the task will start from the date you select. You can choose to have the task continue indefinitely or set an expiration date. Labfront allows several recurrence patterns:

  • Daily
  • Specific Days of the Week
  • Every X Days
  • Multiple Times Per Day




Note

The task duration is currently determined by the Participant's Joined Date. This refers to the date they first signed into the project on the Labfront app. 


Schedule Type: When During the Day?

Once you’ve defined the frequency, you can choose how tasks are timed within the day: Fixed schedule, semi-randomized (EMA), or fully randomized (EMA).

1. Fixed Schedule

The task occurs at specific, consistent times each day.


Best for:

Consistent routines or symptom tracking at set intervals.

  • Morning and evening reflections
  • Time-locked medication or treatment reminders
  • Energy level or sleep quality check-ins

Structure:

  • Specific time (e.g., 9:00 AM)
  • Or regular interval (e.g., every 4 hours)

Example Scenarios:

  • Medication Adherence: "Did you take your meds?"
    • 📅  Every 4 hours between 9:00 AM and 9:00 PM
  • Daily Mood Journal: "How was your mood today?"
    • 📅  Every evening at 9:00 PM


Note

You will need to specify how long the task will remain visible. If not completed in time, it will be marked "Missed" and cannot be completed.

Sample Study

To help understand more about fixed scheduling in Labfront, here's how to use it in  a Labfront sample study.

 

2. Semi-Randomized (EMA)

Tasks occur near regular intervals, but with random variation (flexibility window) to reduce predictability.

Best for:

Capturing natural, time-varying experiences while minimizing predictability and participant burden.

  • Mood or stress tracking
  • Cravings
  • Social interactions

Structure:
 Approximately every X hours ± Y min

Example Scenarios:

  • Fatigue Tracker (Long COVID Study): "How mentally and physically tired do you feel?"
    • 📅 Every 4 hours ± 1 hour, from 7:00 AM to 11:30 PM
  • Craving & Urge Report (Smoking Study): "Are you experiencing any cravings right now?"
    • 📅 Every 5 hours ± 20 minutes, from 10:00 AM–10:00 PM

What's a Flexibility Window?

The flexibility window refers to the time range around a scheduled task when it can be completed. For example, if a task is set for 3:00 PM with a flexibility window of 30 minutes, it can be completed anytime between 2:30 PM and 3:30 PM. This allows for some variability in when the task is executed while still keeping it within a defined timeframe.

 

3. Fully Randomized (EMA)

Tasks are randomly scheduled within a time range, with a minimum interval to avoid clustering.

Best for:

Capturing in-the-moment experiences and reducing predictability bias, or situational triggers that may vary throughout the day.

  • Craving/impulsivity research
  • Mood fluctuations
  • Stress responses

Structure:
X prompts/day, random times, minimum spacing between

 

Example Scenarios:

  • Stress & Coping in Students: "How stressed are you right now?"
    • 📅  3 random prompts between 8:00 AM - 11:00 PM, min. 1 hr apart
  • Dietary Impulse Control: "Have you had cravings in the last 15 minutes?"
    • 📅 4 prompts between 9:00 AM–9:00 PM, min. 90 mins apart

Sample Study

To help understand more about EMA in Labfront, here's how to use it in  a Labfront sample study.

 



🧪 Sample Study: Improving Sleep and Mood Through Daily Monitoring and Medication

To illustrate task scheduling, consider a study on how sleep patterns and short-term medication affect daily mood in adults aged 25–40 over a 5-week period.

 

1. Onboarding Baseline Questionnaire

  • Purpose: Collect demographic data, medical history, and baseline mood/sleep information.
  • Schedule:
    • One-time only

    • Schedule Type: Fixed

    • Visibility: Day 1 at 8:00 AM to Day 7 at 11:59 PM

    • Duration: Day 1 - Day 7

2. Stress, Mood, Energy Level Tracking (EMA)

  • Purpose: Track real-time mood, energy, and stress levels throughout the day.

  • Schedule:

    • Recurring: Daily
    • Schedule Type: Fully randomized
    • Frequency: 5 times per day from 9:00 AM to 9:00 PM
    • Visibility: 30 minutes each instance

    • Duration: From Day 1 - Day 14 & Day 28 - Day 36 







 

3. Sleep Journal

  • Purpose: Capture weekly sleep patterns and sleep quality.

  • Schedule:

    • Recurring: Specific Day of the Week (Saturday)

    • Schedule Type: Fixed

    • Visibility: 7:00 AM to 7:00 PM every Saturday 
    • Duration: From Day 1 to Day 36

 

4. Medication Intervention

  • Purpose: Assess the impact of a 1-week medication intervention on mood and sleep with daily medication check-ins during this period.

  • Schedule:

    • Recurring: Daily

    • Schedule Type: Fixed

    • Visibility: 7:00 AM to 11:00 AM every morning

    • Duration: From Day 8 to Day 14


Pro Tips for Researchers

  • Fixed schedules are best for structured routines (e.g., morning check-ins, medication).
  • Fully or semi-randomized schedules reduce anticipation bias, making them ideal for behavior or mood studies.
  • Consider participant fatigue. 3–5 prompts/day is a common upper limit.
  • Mix and match strategies:
    • Fixed AM check-ins + random daytime assessments
    • Weekly mood check-in + daily reports
  • For long-term studies, gradually reduce frequency to maintain engagement.
  • Set visibility windows that aren't too long to ensure responses are timely.
  • Make sure participants have Labfront notifications turned on.


FAQ

What is a "flexibility window" in semi-randomized scheduling?

 A "flexibility window" allows each task to be delivered within a certain timeframe rather than at a precise scheduled moment. For instance, if prompts are set every 2–3 hours with a flexibility window of ±30 minutes, and the first prompt is at 9:00 AM, it could be sent anytime between 8:30 AM and 9:30 AM.

Can I add multiple schedules to one task?

Yes! You can choose to add more than one schedule to any task. For instance, you may want to schedule the same questionnaire to appear on the first and last day of a study. 

You could add two schedules to the questionnaire task:

Can a participant self-report when something specific happens (event sampling)?

Event-based sampling is coming soon!

What if my schedules overlap?

They will show up as two separate instances and won't cancel each other out.

Why opt for semi-randomized over fully randomized EMA?

Semi-randomized EMA minimizes predictability while still evenly covering the day.