Ecological Momentary Assessment (EMA) - Overview

Choosing and implementing EMA schedules in REDCap

Overview

Ecological Momentary Assessment (EMA) involves collecting data from participants multiple times throughout their daily lives. REDCap offers several approaches to implement EMA, each with different trade-offs in complexity, flexibility, and maintenance.

This is also known as Experience Sampling or Experience Sampling Methods, or ES / ESM. In this book, we’re sticking to EMA.

This guide will help you choose the right approach for your study.

Choosing an Approach

Decision Guide

Fixed Schedule

• Sample times are the same for all participants
• Schedule doesn’t need to adapt based on participant responses
• You want the simplest possible implementation

Random Schedule (Automatic)

• You need random/semi-random sampling within defined windows
• The schedule can be fully determined up-front
• You can set up as many events and Automated Survey Invitations (ASIs) as you will have samples
• You want everything managed within REDCap (no external tools needed to compute schedules)

Random Schedule (Flexible)

• You need random sampling but want flexibility to adjust schedules
• You want to more tightly control sampling constraints (minimum spacing, etc.)
• You can use an external tool or script (R, Python, or spreadsheets) to generate schedules
• You can use the Data Import Tool or API
• You don’t need REDCap’s built-in survey reminder/expiration features

Comparison Table

Feature	Fixed	Random (Automatic)	Random (Flexible)
Setup complexity	Low	High	Medium
Requires external tools	No	Yes (event / ASI mapping)	Yes (schedule generation)
Can adjust schedules after start	Limited	No	Yes
Supports custom spacing rules	No	Limited	Yes
Supports survey reminders	Yes	Yes	Manual implementation
Supports survey expiration	Yes	Yes	Manual implementation