The SMART is an experimental design that researchers can use to efficiently answer multiple scientific questions concerning the selection and integration of the components that make up an adaptive intervention. A SMART involves multiple stages of randomizations, meaning that some or all individuals participating in a SMART are randomized more than once. This is the SMART’s defining feature.

When developing a Just-in-Time Adaptive Intervention, investigators often have scientific questions about how to best deliver and adapt momentary interventions in the real world. A Micro-Randomized Trial (MRT) helps investigators answer these questions. The MRT is a randomized trial that includes rapid sequential randomizations. This means that the same person may be repeatedly randomized to intervention options hundreds or thousands of times during a trial.

Hybrid Experimental Designs (HED) can be used to answer scientific questions about the integration of human-delivered and digital components and their adaptation at multiple timescales. Researchers can use HEDs to design effective Multimodal Adaptive Interventions (MADI). Various hybrid experimental designs are possible, such as hybrids of a standard factorial design with a SMART or an MRT, or a hybrid combining a SMART and an MRT.

Multilevel Implementation SMARTs (MI-SMART) are a type of experimental study design used to construct an optimized Multilevel Adaptive Implementation Strategy (MAISY). In a MI-SMART, there are multiple levels (e.g., clinic and providers within clinic) and multiple time points of randomization. These randomizations help us answer scientific questions about how best to sequence and adapt different strategies across multiple levels of implementation.