Intention-to-treat Analysis in Partially Nested Randomized Controlled Trials with Real-World Complexity

Published in: International Journal of Research & Method in Education, v. 39, no. 3, 2016, p. 268-286

Posted on RAND.org on June 10, 2016

by Jonathan Schweig, John F. Pane

Read More

Access further information on this document at International Journal of Research & Method in Education

This article was published outside of RAND. The full text of the article can be found at the link above.

Demands for scientific knowledge of what works in educational policy and practice has driven interest in quantitative investigations of educational outcomes, and randomized controlled trials (RCTs) have proliferated under these conditions. In educational settings, even when individuals are randomized, both experimental and control students are often grouped into particular classrooms and schools and share common learning experiences. Analyses that account for these clusters are common. A less common design involves one clustered experimental arm and one unclustered experimental arm, sometimes called a partially clustered design. Analysts do not always use methods that yield valid statistical inferences for such partially clustered designs. Additionally, published methods for handling partially clustered designs may not be flexible enough to handle real-world complications, including treatment non-compliance. In this paper, we illustrate how models that accommodate partial clustering may be used in educational research. We explore the performance of these models using a series of Monte Carlo simulations informed by data taken from a large-scale RCT studying the impacts of a programme designed to decrease summer learning loss. We find that clustering and non-compliance can have substantial impacts on statistical inferences about intent-to-treat effects, and demonstrate methods that show promise for addressing these complications.

This report is part of the RAND Corporation External publication series. Many RAND studies are published in peer-reviewed scholarly journals, as chapters in commercial books, or as documents published by other organizations.

Our mission to help improve policy and decisionmaking through research and analysis is enabled through our core values of quality and objectivity and our unwavering commitment to the highest level of integrity and ethical behavior. To help ensure our research and analysis are rigorous, objective, and nonpartisan, we subject our research publications to a robust and exacting quality-assurance process; avoid both the appearance and reality of financial and other conflicts of interest through staff training, project screening, and a policy of mandatory disclosure; and pursue transparency in our research engagements through our commitment to the open publication of our research findings and recommendations, disclosure of the source of funding of published research, and policies to ensure intellectual independence. For more information, visit www.rand.org/about/principles.

The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.