A JITAI is a form of an adaptive intervention intended to address the rapidly changing needs of individuals. JITAIs use dynamically changing information about the individual’s internal state (e.g., craving, stress) and context (e.g., physical location) to recommend whether and how to deliver interventions in real time, in the person’s natural environment.

For example, a JITAI to improve physical activity levels in individuals with spinal cord injury (Hiremath et al., 2019) monitors the person’s wheelchair-based physical activity continuously via a smartwatch and a wheel rotation monitor. Every minute, if the participant performed at least 3 continuous minutes of moderate-intensity (or higher) physical activity, a personalized feedback prompt is delivered through the smartphone (audio and/or vibration: based on the participant’s choice) and smartwatch (vibration). Otherwise a feedback prompt is not delivered.

Similar to standard adaptive interventions, a JITAI is protocolized with decision rules that specify whether and how to intervene depending on the person’s changing needs.

JITAIs play a critical role in many fields, including in addiction (see Carpenter et al., 2020), mental health, physical activity and weight loss (see Nahum-Shani et al., 2018).


Carpenter, S. M., Menictas, M., Nahum-Shani, I., Wetter, D. W., & Murphy, S. A. Developments in Mobile Health Just-in-Time Adaptive Interventions for Addiction Science. Curr Addict Rep 7, 280–290 (2020).

Hiremath, S. V., Amiri, A. M., Thapa-Chhetry, B., Snethen, G., Schmidt-Read, M., Ramos-Lamboy, M., . . . Intille, S. S. (2019). Mobile health-based physical activity intervention for individuals with spinal cord injury in the community: A pilot study. PloS one, 14(10), e0223762.

Nahum-Shani, I., Hekler, E. B., & Spruijt-Metz, D. (2015). Building health behavior models to guide the development of just-in-time adaptive interventions: A pragmatic framework. Health Psychology, 34(S), 1209.

Nahum-Shani, I., Smith, S. N., Spring, B. J., Collins, L. M., Witkiewitz, K., Tewari, A., & Murphy, S. A. (2018). Just-in-Time Adaptive Interventions (JITAIs) in Mobile Health: Key Components and Design Principles for Ongoing Health Behavior Support. Annals of Behavioral Medicine, 52, 446-462. doi:10.1007/s12160-016-9830-8.

d3lab specializes in developing new methods for optimizing Just in Time Adaptive Interventions, including new approaches for the design and analysis of Micro-Randomized Trials (MRTs).

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