CalFit EMA — Smartphone-based Ecological Momentary Assessment

CalFit EMA allows researchers to conduct Ecological Momentary Assessments (EMAs) using smartphones.

EMAs are short surveys — a few questions — that occur during random times during the day.  They measure in-the-moment actions, emotions, and location.  The use of smartphones for EMA takes advantage of the fact that many people are already used to and comfortable with carrying their phone, and responding during the day to phone calls, text messages, emails, calendar events, etc.  Mobile EMAs capture what traditional paper questionnaires and direct observation studies cannot because researchers cannot following subjects for long periods of time (and even if they did so they would likely alter the subjects’ behaviors).

CalFit EMA is part of the CalFit system of apps.  CalFit EMA together with CalFit D (a time-location and physical activity tracker) provides rich contextual sensing of an individuals health.

CalFit EMA is extremely flexible.  It has these features:

  • Runs on inexpensive Android 2.3.3+ phones (e.g., ~$130 Samsung Galaxy Y phone).
  • Completely customizable questionnaires.
  • Can be used with or without a SIM-activated Android phone.
  • Using a SIM-activited phone with a mobile data plan allows for real-time data uploading to an Internet server.  If used without a SIM, data are simply stored on the phone’s memory card, and researchers can download the data later.
  • The phone logs times and locations when EMAs are completed allowing for studies of both temporal and spatial contextual factors.









CalFit EMA was developed by Dr. Seto through a grant from the NIH NIEHS R01ES020409.

If interested in using CalFit EMA, contact Dr. Seto.

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