The process of repeatedly collecting and studying data from people about their current behaviors and experiences in real-time has many names. While these terms are often used interchangeably, each has a general identifying characteristic. Here's a list of each of them:


The experience sampling method was developed by Larson and Csikszentmihalyi (1983). By definition, ESM is a research procedure for studying what people do, feel, and think during their daily lives by asking them to provide systematic self-reports on random occasions during the waking hours of a normal week. It obtains information about the private as well as the public aspects of individuals' lives, secures data about behavioral and intrapsychic aspects of daily activity, and obtains reports about people's experiences as they occur, thereby minimizing the effects of reliance on memory and reconstruction.

Whilst gathering information from people during their daily lives is the primary role of Experience Sampling, the term has become used to describe gathering subjective data over time even within the laboratory or clinical setting.


Stone and Shiffman (1994) coined the term Ecological momentary assessment. EMA involves repeated sampling of a person's current behavior and experiences in real-time, in his/her natural environment. It aims to avoid or minimize retrospective memory biases, maximize ecological validity, and allow the study of micro-processes that influence behavior in real-world contexts.

Ecological Momentary Assessment emerged out of the field of behavioral medicine, and as a result, often includes physiological parameters or health-related questions.

ESM and EMA arose from different research traditions, they have in common the collection of self-reports or indices of behavior, cognition, or emotions in near real-time in the daily lives of the participants, ideally with electronic devices.


Diary Studies involve intensive, repeated self-reports that aim to capture events, reflections, moods, pains, or interactions near the time they occur. In a diary study, data is self-reported by participants longitudinally - that is, over an extended period of time that can range from a few days to even a month or longer. During the defined reporting period, study participants are asked to keep a diary and log specific information about activities being studied.


Ambulatory Assessment represents a methodological umbrella that encompasses increasingly computerized or digitized methods of experience sampling, ecological momentary assessment, and continuous psychophysiological, biological, and behavior monitoring (typically using sensors or actigraphs). It comprises the use of field methods to assess the ongoing behavior, physiology, experience and environmental aspects of people in naturalistic or unconstrained settings. It uses ecologically-valid tools to understand biopsychosocial processes as they unfold naturally in time and in context.

Whilst ESM, EMA and Daily Diary Studies are components of Ambulatory Assessment, this term often conjures Physiological Monitoring to mind. Research papers that cite Ambulatory Assessment in their keywords often utilize accelerometers, ECG, and other physiological parameters as the main data in their study.