EMA: Fixed Schedule

ema
survey
scheduling
asi
Implementing EMA with a fixed, predictable schedule using Automated Survey Invitations
Published

January 9, 2026

Overview

Problem: You need to collect EMA data from participants at predetermined times — for example, a daily diary every morning at 9AM.

Solution: Use a repeating instrument with an Automated Survey Invitation (ASI)

Prerequisites

  • An email field for participants
  • Project Setup and Design rights
  • Alerts & Notifications rights

When to Use This Approach

Fixed schedules work well when:

  • All participants receive surveys at the same times
  • The schedule is predictable and consistent
  • You want minimal setup complexity
  • Participants knowing the schedule isn’t a concern

See the EMA overview for other approaches.

Steps

Create the Welcome survey

  1. Create a new instrument called welcome
  2. Add an email field to capture the participant’s email address:
    • Field Type: Text Box
    • Validation: Email
    • Variable Name: email
  3. Enable the instrument as a survey in Designer > Enable (click the instrument options icon)
  4. In Project Setup > Designate an email field for communications, select email

Create the Diary instrument

  1. Create a new instrument called diary
  2. Add your data collection fields.
  3. Enable the instrument as a survey; set its Survey settings how you want them

Set up the Diary as a Repeating Instrument

  1. Go to Project Setup > Repeating instruments
  2. Click Enable
  3. Configure the repeating instruments:
    • Check the box next to diary

Create the ASI

  1. Go to Designer and click Survey Settings for the diary instrument
  2. Enable Automated Invitations
  3. Set the Conditions so the logic is appropriate for your study. In the example, set it to when the welcome survey is completed.
  4. Set When to send… as you want them. If you’re testing, you might want Send immediately. For a daily diary you might want 9 AM.
  5. Set How many times to send it as you want. For testing, you might set this to send a few times, every 5 minutes. For a real diary, you might have it send once a day for 30 days.

Notes

  • Timing precision: How often REDCap sends scheduled messages depends on your instance’s server settings. Our server sends scheduled messages every 5 minutes. Send immediately alerts are generally not subject to this delay.
  • First survey timing: The first diary invitation will be sent on the next scheduled time after the welcome survey is completed. If a participant completes the welcome survey at 2 PM and you’ve scheduled surveys for 9 AM, they’ll receive their first diary survey the next morning at 9 AM.
  • New instance behavior: Each survey invitation creates a new repeating instance of the diary instrument. You don’t need to manually create instances with [new-instance]
  • Time zones: REDCap uses the server’s time zone for all automated invitations. Taking time zones into account is a subject for another recipe.
  • Stopping the invitations: To stop surveys for participants who withdraw, see Stopping Alerts and ASIs
  • Survey expiration: Setting an expiration (e.g., 24 hours) can help keep data collection timely, but consider your participants’ schedules and availability
  • Other contact methods: The exact same practices apply if you’re using an SMS provider such as Twilio or Mosio.
Warning

Remember the server schedule delay when you are troubleshooting!

Troubleshooting

  • Verify the ASI is active and saved
  • Confirm the condition logic evaluates to true for the records you expect
  • Check that the email field is really the designated email field
  • Check Survey Distribution Tools > Survey Invitation Log to see scheduled and sent invitations
Warning

During the time between when a survey is scheduled and when it is sent, it will not appear in the Survey Invitation Log at all.