EMA only works if people answer close to the moment. Capture sends short phone-browser surveys on a schedule, reminds participants by email or SMS, closes entries with completion windows and shows you who is falling behind, with no app to install.
Free sandbox · No credit card · 21 CFR Part 11 aligned
When due
18:00
Your evening diary is open
Next day
18:00
Reminder: your diary is still open
Final notice
21:30
Last chance before the window closes
Quiet hours
22:00 to 08:00 in the participant's time zone
Stops
As soon as the task is completed
What EMA needs from software
The method
Ecological momentary assessment (EMA), also called experience sampling, asks people to report what they feel, do or experience in daily life, close to the moment it happens, repeatedly over days or weeks. The aim is to reduce recall bias and to see variation within a person: mood across a day, pain after activity, craving before a lapse, stress before an exam. The unit of analysis is the prompt, so a missed or late prompt is not a small gap; it is a missing observation, and entries filled in from memory hours later weaken exactly what the method is for.
That makes three software properties matter more than a polished interface. Prompts must arrive reliably and not at night. Late entries must be handled by a rule you chose in advance, not by whoever opens the questionnaire next. And you must be able to see compliance while the study is running, not in the analysis. The same properties protect diary endpoints in clinical trials, which is why EMA studies fit an ePRO platform well. See ePRO software for clinical trials for the wider feature set.
A one-off questionnaire collects a single retrospective report. A diary usually collects one entry a day. EMA collects short entries more often and nearer the moment. Capture's scheduling, windows and reminders serve all three; the practical difference is how short each task must be and how tight the window. See patient diary software for the daily-diary case.
Window -3 / +3 days around the anchored target date
Soft window
Stays available with a protocol deviation flag
Hard window
Locks outside the window
Warning only
Stays available with a warning
Auto-close
Marked missed when the window closes
Timing control
Choose, per task, how strictly a window is enforced. A hard window stops people from back-filling a day of prompts in the evening. A softer one suits less critical items. Auto-close marks an unanswered entry as missed, so your dataset records a missing observation instead of a late guess.
Window -3 / +3 days around the anchored target date
Soft window
Stays available with a protocol deviation flag
Hard window
Locks outside the window
Warning only
Stays available with a warning
Auto-close
Marked missed when the window closes
Design choices
| Decision | Typical options | Where it lives in Capture |
|---|---|---|
| Prompt length | A handful of items, about a minute | Short form from the 10 question types; skip logic to shorten on easy days |
| How answers are given | Sliders, scales, choices, free text | Slider, linear scale, single and multiple choice, dropdown, numeric, text, long text, date, time |
| Reminder rhythm | Prompt, one nudge, last call | Reminder ladder: when due, next day, before the window closes |
| Late entries | Allow, warn or reject | Window mode: soft, hard, warning-only, auto-close |
| Night-time messages | None | Quiet hours in the participant's own time zone |
| Recruitment | Posters, clinic, online | QR codes, site-specific or study-specific |
| Monitoring | Weekly compliance check | Compliance by study, country and site; at-risk participants and overdue tasks |
Build a short EMA form in the free sandbox, scan the QR code and receive your own reminders. No credit card.
Good practice
Participation fatigue is the main threat. Keep each prompt to the items you will actually analyse, ask people to rate the moment rather than the day, and use skip logic so a "no symptoms" answer ends the form early. Pilot with a few colleagues first: if they find the schedule intrusive, participants will too. The free sandbox is the right place to find that out, because you can enrol yourself and see how the reminder ladder feels on a real phone.
Agree the message rhythm at consent. People accept prompts more readily when they were told what to expect, and quiet hours should match their sleep, not your working day. The pre-screening consent template and the ePRO enrollment consent template are useful starting points for your ethics submission.
Review compliance weekly. Capture flags at-risk participants and overdue tasks, so a short human check-in can happen before a participant drifts away. For a first look at mood and fatigue designs, the mood tracker, sleep diary and fatigue log templates show the structure of a short repeated form. These are templates for building your own questionnaire; if you add a published scale, check the rights holder's licence terms yourself.
After collection
EMA data are nested: many prompts within each participant. The export gives one row per submission in wide format with an automatic data dictionary, so each prompt is a row you can load into the multilevel or mixed-model software you already use. Decide before you start how a missed entry should appear in the analysis. With auto-close windows the entry is marked missed rather than absent, which makes compliance rates straightforward to compute per participant and per day.
Plan the compliance threshold in advance as well. Many studies set a minimum share of answered prompts for a participant to enter the analysis, and report overall compliance in the methods. Capture shows compliance by study, country and site while the study is running, so you can see whether a threshold is realistic early enough to change the schedule, rather than discovering it at the end. Date and time fields on each entry let you examine time-of-day patterns, and you can filter exports by date range for interim looks.
For studies that combine EMA with clinic visits, keep the repeated surveys and the visit forms in one study so identifiers line up. See ePRO for patient-reported outcome studies for how repeated questionnaires and visit assessments sit side by side.
The difference
Setup
Number and timing of prompts per day, and study length.
Only items you will analyse, built from the 10 question types.
Hard for momentary items, softer for end-of-day items.
Agreed with participants at consent.
QR code on posters or leaflets, with ethics approval for the wording.
Weekly check of at-risk participants.
Confirm in the sandbox that your sampling schedule fits before going live.
No. Reminders carry a secure link that opens the survey in the phone browser, and QR enrolment also opens in the browser.
Up to three reminders per task: when it is due, the next day, and a final notice before the window closes. Reminders stop as soon as the task is done.
Yes. Reminders respect quiet hours in each participant's own time zone, and a daily message cap applies.
You choose per task: soft, hard, warning-only or auto-close, where an unanswered entry is marked missed.
Ten: short text, numeric, linear scale, slider, single choice, multiple choice, dropdown, date, time and long text.
Yes. Compliance is shown by study, country and site, with at-risk participants and overdue tasks flagged.
The study team can enable a device connection per study, and participants connect their own account through the vendor's sign-in. Oura is the device we name. Confirm the device you need before you plan around it.
Yes. The free sandbox has every feature, no credit card and no time limit; you pay only when you go live with real participants.
Keep exploring
ePRO reminders by SMS and email
The reminder ladder in detail.
Patient diary software
Daily diaries.
BYOD ePRO, no app
Surveys on participants' own phones.
QR code participant enrolment
Recruit from a poster.
EDC for behavioral health studies
Behavioural designs.
ePRO for observational studies
Repeated reporting without an intervention.
Scheduled surveys, reminders and windows. Free sandbox.