Is it possible to conduct a sufficiently powered factorial experiment if I have a multilevel structure to contend with?


Yes! This is possible even when cluster randomization is necessary. For more about this see Dziak, Nahum-Shani, and Collins (2012), Nahum-Shani, Dziak, & Collins (2018), and Nahum-Shani and Dziak (2018).

Note that if one or more intervention components are group-based, there is probably a multi-level structure.  This is discussed in Nahum-Shani et al. (2018).


Dziak, J. J., Nahum-Shani, I., & Collins, L. M. (2012). Multilevel factorial experiments for developing behavioral interventions: Power, sample size, and resource considerations. Psychological Methods, 17(2), 153-175.

Nahum-Shani, I., Dziak, J. J., & Collins, L. M. (2018). Multilevel factorial designs with experiment-induced clustering. Psychological Methods, 23(3), 458-479.

Nahum-Shani, I., Dziak, J. J. (2018). Multilevel factorial designs in intervention development.  In Collins, L. M., & Kugler, K. C. (Eds.), Optimization of behavioral, biobehavioral, and biomedical interventions: Advanced topics. New York: Springer.

Share This…

All Frequently Asked Questions

Search FAQs

Search FAQs text
FAQ category

Further Learning

Whether you are looking for additional support as you prepare a grant proposal involving MOST or practical information helpful in managing your optimization trial, this section provides resources for a deeper dive into intervention optimization.

REDCap with Most

The goal of this manual is to show how one might setup a REDCap project to support a research study with multiple conditions, such as factorial experiments common in the Multiphase Optimization Strategy (MOST) framework.

Informal introduction to factorial experimental designs

The purpose of this page is to clarify some concepts, notation, and terminology related to factorial experimental designs, and to compare and contrast factorial experiments to randomized controlled trials (RCTs). A more in-depth introduction can...


Join the CADIO Mailing List

Keep up to date with the latest news, events, online courses, and resources from CADIO.