Intention-to-Treat Analysis: A Primer for Those Not In “The Stats Club”
In Patrick Wolf’s work with other researchers on this study of late, Student Attainment and the Milwaukee Parent Choice Program: A Final Follow-Up Analysis, Wolf et al. use a statistical analysis know as the Intention-to-Treat (ITT) analysis. In this post, I will explain the analysis, discuss its original intended usage, and discuss its application to Wolf’s work, including limitations.
This post is meant to serve as a not-too-scary primer on ITT.
The Intention-to-Treat (ITT) analysis originates with medical research. In ITT, the researchers “intend” to treat patients in the study according to any number of treatment regimens with the goal of addressing a single medical issue (e.g., cancer). Studies might also include a control group (a group receiving no treatment).
Even though the researchers “intend” to treat patients in the study, patients do not always follow the treatment protocol, or they might manifest some reaction that might require discontinuance. Researchers could exclude such “noncompleters” from the study; however, doing so would disturb the randomized design of the study (random assignment to groups helps ensure that groups are balanced regarding demographic characteristics,
This post is meant to serve as a not-too-scary primer on ITT.
The Intention-to-Treat (ITT) analysis originates with medical research. In ITT, the researchers “intend” to treat patients in the study according to any number of treatment regimens with the goal of addressing a single medical issue (e.g., cancer). Studies might also include a control group (a group receiving no treatment).
Even though the researchers “intend” to treat patients in the study, patients do not always follow the treatment protocol, or they might manifest some reaction that might require discontinuance. Researchers could exclude such “noncompleters” from the study; however, doing so would disturb the randomized design of the study (random assignment to groups helps ensure that groups are balanced regarding demographic characteristics,