Purpose

The purpose of this video lecture is to explain what Randomized Control Trails (RCTs) are and the rationale for conducting them. Additionally, the lecture discusses statistical misunderstandings involving cluster randomized controlled trials (cRCTs) through looking at examples from the field and strategies to improve precision in RCTs. Also, the lecture discusses ethics in RCTs.

Randomization by cluster accompanied by an analysis appropriate to randomization by individual is an exercise in self-deception, however, and should be discouraged." Cornfield (1978) pp.101

Meet the Guest Speaker

Michael Oakes is Interim Vice President for Research and a Professor of Epidemiology at the University of Minnesota. He is a social epidemiologist with scholarly interest in social epidemiology, quantitative methods, and research ethics. He is co-editor and author of /Methods in Social Epidemiology/ and an Associate Editor for the American Journal of Epidemiology. Prior to joining the University’s administration, Dr. Oakes taught graduate seminars in advanced epidemiologic methods, social epidemiology, cluster-randomized trials, statistical programming, and research ethics.

Video Lecture

The video lecture is broken into three main parts: SRTs: Background (Part 1 and Part 2 videos), SRTs: context (Part 1 and Part 2 videos), and SRTs: Analytics (Part 1, Part 2, and Part 3 videos).

Please click each tab to watch each part of the video lecture.

cRCTs: Background
cRCTs: Context
cRCTs: Analytics

cRCTs: Background (Part 1)

cRCTs: Background (Part 2)

cRCTs: Context (Part 1)

cRCTs: Context (Part 2)

cRCTs: Analytics (Part 1)

cRCTs: Analytics (Part 2)

cRCTs: Analytics (Part 3)

Accessibility Note: To access auto closed captions (CC) services please click on the icon in the video's bottom right corner. Manual CC are available by submitting a request for services to ATAC: (812) 856-4112 or atac@iu.edu

NOTE: Please click on the link below to download the video lecture slides:

Cluster Randomized Trials (cRCTs)

Readings

Below is a list of suggested readings relating to this topic that may be of interest for you:

Brown, A. W., Li, P., Bohan Brown, M. M., Kaiser, K. A., Keith, S. W., Oakes, J. M., & Allison, D. B. (2015). Best (but oft-forgotten) practices: designing, analyzing, and reporting cluster randomized controlled trials. The American journal of clinical nutrition, 102(2), 241-248. https://doi.org/10.3945/ajcn.114.105072
Hannan, P. J. (2006). Experimental Social Epidemiology--Controlled Community Trials. In J. M. Oakes & J. S. Kaufman (Eds.), Methods in social epidemiology (pp. 341–369). Jossey-Bass/Wiley.
Shadish, W. R., & Cook, T. D. (2009). The renaissance of field experimentation in evaluating interventions. Annual review of psychology, 60, 607-629. https://doi.org/10.1146/annurev.psych.60.110707.163544

Estimate cRCT Sample Size and Power Yourself

What is the power when you have few clusters, even if you have hundreds of subjects in each cluster? Try the calculator by selecting the image below, made by Greyson Foote with our Biostatistics Consulting Center.