SMARTs with Longitudinal Outcomes

Nicholas J. Seewald

Last updated on May 1, 2025

SMARTs are randomized trials in which some or all participants are randomized more than once, often with the goal of constructing a high-quality dynamic treatment regime (DTR). This work provides applied scientists with design tools needed to power a SMART when the primary goal is to compare two embedded DTRs on a continuous outcome collected over the course of multiple stages of randomization.

SMARTs DTRs methods

Publications

Design and Analytic Considerations for Sequential, Multiple-Assignment Randomized Trials with Longitudinal Outcomes

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Statistics)in the University of Michigan.

Nicholas J. Seewald

Sample Size Considerations for Comparing Dynamic Treatment Regimens in a Sequential Multiple-Assignment Randomized Trial with a Continuous Longitudinal Outcome

Clinicians and researchers alike are increasingly interested in how best to personalize interventions. A dynamic treatment regimen is a …

Nicholas J. Seewald, Kelley M. Kidwell, Inbal Nahum-Shani, Tianshuang Wu, James R. McKay, Daniel Almirall

Events

Dissertation defense: Design and analytic considerations for sequential, multiple-assignment randomized trials with longitudinal outcomes

A dissertation defense completed in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Statistics) at the University of Michigan.

May 10, 2021 10:00 AM — 11:30 AM Virtual

Nicholas J. Seewald

Dissertation defense: Design and analytic considerations for sequential, multiple-assignment randomized trials with longitudinal outcomes

Budgeting SMART: Sample size and repeated measures with a cost constraint in a longitudinal sequential, multiple-assignment randomized trial

A contributed oral presentation at ENAR 2021.

Mar 17, 2021 3:00 PM — 3:20 PM Virtual

Nicholas J. Seewald, Daniel Almirall

Sample size and timepoint tradeoffs for comparing dynamic treatment regimens in a longitudinal SMART

A contributed oral presentation at JSM 2020.

Aug 4, 2020 10:00 AM — 2:00 PM Virtual

Nicholas J. Seewald, Daniel Almirall

Sample size and timepoint tradeoffs for comparing dynamic treatment regimens in a longitudinal SMART

Design considerations for comparing dynamic treatment regimens in a longitudinal SMART

A contributed oral presentation at ENAR 2020.

Mar 23, 2020 11:30 AM — 11:45 AM Virtual

Nicholas J. Seewald, Daniel Almirall

Sample size considerations for comparing dynamic treatment regimes in a SMART with a longitudinal outcome

An oral presentation given as part of an invited session at CMStatistics 2019 on recent advances in methods for dynamic treatment regimes.

Dec 16, 2019 4:35 PM — 5:50 PM London, GB

Nicholas J. Seewald, Daniel Almirall

Sample size considerations for comparing dynamic treatment regimens in a SMART with a longitudinal outcome

A contributed oral presentation at JSM 2019.

Jul 30, 2019 8:35 AM — 8:50 AM Denver, CO, USA

Nicholas J. Seewald, Kelley M. Kidwell, James R. McKay, Inbal Nahum-Shani, Tianshuang Wu, Daniel Almirall

Sample size considerations for comparing dynamic treatment regimens in a SMART with a longitudinal outcome

Sample size considerations for comparing dynamic treatment regimens in a sequentially-randomized trial with a continuous longitudinal outcome

A contributed oral presentation at the 2019 Society for Clinical Trials Annual Meeting.

May 20, 2019 2:00 PM — 3:00 PM New Orleans, LA, USA

Nicholas J. Seewald, Kelley M. Kidwell, Inbal Nahum-Shani, Tianshuang Wu, James R. McKay, Daniel Almirall

Sample size considerations for comparing dynamic treatment regimens in a sequential multiple-assignment randomized trial with a continuous longitudinal outcome

A poster presented at the 2019 Michigan Student Symposium for Interdisciplinary Statistical Sciences.

Mar 29, 2019 10:00 AM — 11:15 AM University of Michigan, Ann Arbor, MI, USA

Nicholas J. Seewald, Daniel Almirall

Sample size considerations for comparing dynamic treatment regimens in a sequential multiple-assignment randomized trial with a continuous longitudinal outcome

An oral presentation for a topic contributed session at JSM 2018 on “issues and advances in power calculations for mental health studies”.

Jul 30, 2018 9:35 AM — 9:55 AM Vancouver, British Columbia, Canada

Nicholas J. Seewald, Kelley M. Kidwell, Inbal Nahum-Shani, Tianshuang Wu, James R. McKay, Daniel Almirall

Sample size considerations for comparing dynamic treatment regimens in a sequential multiple-assignment randomized trial with a continuous longitudinal outcome

Sample size considerations for comparing dynamic treatment regimens in a sequential multiple-assignment randomized trial with a continuous longitudinal outcome

A poster presented during the 7th Annual Thomas R. Ten Have Symposium on Statistics in Mental Health.

Jun 7, 2018 4:20 PM — 6:20 PM Northwestern University, Chicago, IL, USA

Nicholas J. Seewald, Kelley M. Kidwell, Inbal Nahum-Shani, Tianshuang Wu, James R. McKay, Daniel Almirall

Sample size considerations for comparing dynamic treatment regimens in a sequential multiple-assignment randomized trial with a continuous longitudinal outcome

Sample size considerations for comparing dynamic treatment regimes in a sequential multiple-assignment randomized trial with a continuous longitudinal outcome

A contributed oral presentation at the 2018 ENAR Spring Meeting.

Mar 27, 2018 2:00 PM — 2:15 PM Atlanta, GA, USA

Nicholas J. Seewald, Kelley M. Kidwell, James R. McKay, Inbal Nahum-Shani, Daniel Almirall

Sample size considerations for the analysis of continuous repeated-measures outcomes in sequential multiple-assignment randomized trials

A poster presented at the 2017 Michigan Student Symposium for Interdisciplinary Statistical Sciences. Winner, Best Departmental Poster (Statistics).

Mar 24, 2017 12:00 PM — 1:00 PM University of Michigan, Ann Arbor, MI, USA

Nicholas J. Seewald, Inbal Nahum-Shani, James R. McKay, Daniel Almirall