Nicholas J. Seewald

About Me

I am a second-year Ph.D. student in the Department of Statistics at the University of Michigan, working with Susan A. Murphy, Ph.D. on design and analysis methods for micro-randomized trials in the setting of mobile health interventions. I am a member of the Statistical Reinforcement Learning Lab at the University of Michigan.

Previously, I worked with Kelley M. Kidwell, Ph.D. in the Department of Biostatistics at Michigan. This work involved sample size calculation for sequential, multiple-assignment, randomized trials with binary outcomes, and collaboration on several projects with clinicians in the University of Michigan Cancer Center. My cancer-related work was done as a trainee on an NIH-funded training grant for cancer biostatistics1 NIH 5T32CA083654-12 (P.I. Jeremy M.G. Taylor, Ph.D.).

As an undergraduate at the University of Notre Dame, I worked with Seth N. Brown, Ph.D. on kinetics of reduction-oxidation reactions involving molybdenum complexes. I wrote my undergraduate thesis on Shannon entropy and its applications in combinatorics under the direction of David Galvin, Ph.D.

Key interests: Sequential decision making, dynamic treatment regimes, just-in-time adaptive interventions, sequential multiple assignment randomized trials, micro-randomized trials, clinical trials, experimental design, biostatistics


  • Doctor of Philosophy (in progress) Statistics, University of Michigan
  • Master of Science Biostatistics, University of Michigan, 2015
  • Bachelor of Science Mathematics with Life Sciences, University of Notre Dame, 2013, cum laude

Research Interests

Broadly, my interests lie in sequential decision-making, particularly in the context of health and medicine. Specifically, I am interested in methods in clincal trial design which allow for the construction of effective dynamic treatment regimes which are useful in making clinical decisions.

Currently, my focus is on design and analysis methods for micro-randomized trials in the setting of mobile health. At the moment, the majority of my work involves data management and analysis for HeartSteps, a micro-randomized trial seeking to investigate the effects of providing contextually-aware suggestions on physical activity levels in sedentary adults.

My previous work largely focused on sample size calculation for sequential, multiple-assignment, randomized trials (SMARTs) with a binary outcome. To this end, I created an online sample size calculator for use by clinicians, a beta version of which is available here.



  • Hertz, D. L., Kidwell, K. M., Seewald, N. J., Gersch, C. L., Desta, Z., Flockhart, D. A., ... Rae, J. M. (2016), "Polymorphisms in drug-metabolizing enzymes and steady-state exemestane concentration in postmenopausal patients with breast cancer," The Pharmacogenomics Journal.
  • Kadakia, K. C., Snyder, C. F., Kidwell, K. M., Seewald, N. J., Flockhart, D. A., ... Henry, N. L. (2016), "Patient-Reported Outcomes and Early Discontinuation in Aromatase Inhibitor-Treated Postmenopausal Women With Early Stage Breast Cancer," The Oncologist.
  • Hertz, D. L., Caram, M. V., Kidwell, K. M., Thibert, J. N., Gersch, C., Seewald, N. J., ... Cooney, K. A. (2016), "Evidence for association of SNPs in ABCB1 and CBR3, but not RAC2, NCF4, SLC28A3 or TOP2B, with chronic cardiotoxicity in a cohort of breast cancer patients treated with anthracyclines," Pharmacogenomics.
  • Randolph, A. H., Seewald, N. J., Rickert, K. and Brown, S. N. (2013), "Tris (3, 5-di-tert-butylcatecholato) molybdenum (VI): Lewis Acidity and Nonclassical Oxygen Atom Transfer Reactions," Inorganic Chemistry.
  • Marshall-Roth, T., Liebscher, S. C., Rickert, K., Seewald, N. J., Oliver, A. G. and Brown, S. N. (2012), "Nonclassical oxygen atom transfer reactions of oxomolybdenum(vi) bis(catecholate)," Chemical Communications.

Pre-Prints and Abstracts

  • Seewald, N. J., Sun, J., Liao, P. (2016) "MRT-SS Calculator: An R Shiny Application for Sample Size Calculation in Micro-Randomized Trials," arXiv:1609.00695 [stat.ME].
  • Hertz, D.L., Kidwell, K.M., Seewald, N.J., Gersch, C.L., Desta, Z., Flockhart, D.A., Storniolo, A.M., Stearns, V., Skaar, T.C., Hayes, D. F., Henry, N.L., and Rae, J.M. (2016), "Abstract P5-12-05: CYP3A4* 22 polymorphism is associated with increased exemestane concentrations in postmenopausal breast cancer patients," Cancer Research, 76, 4 [supplement], P5-12.
  • Kadakia, K.C., Kidwell, K.M., Seewald, N.J., Snyder, C.F., Flockhart, D.A., Otte, J.L., Hayes, D.F., Storniolo, A.M., Stearns, V., and Henry, N.L. (2016), "Crossover from One Aromatase Inhibitor (AI) to Another in the Exemestane and Letrozole Pharmacogenetics (ELPh) Trial," Journal of Clinical Oncology, 34, 3 [supplement], 158.
  • Mammoser, A.G., Weathers, S.S., Seewald, N.J., Taylor, J.M. and Junck, L. (2015), "Primary CNS lymphoma; a review of the University of Michigan experience 2004-2013," Journal of Clinical Oncology, 33, 15[supplement] e13012.
  • Kadakia, K. C., Snyder, C. F., Kidwell, K. M.,Seewald, N. J., Storniolo, A. M., ... Henry, N. L. (2015), " Associations between treatment-emergent symptoms and early discontinuation of aromatase inhibitor (AI) therapy," ASCO Meeting Abstracts Online, 33, e20745.

In Progress

  • Seewald, N. J., Kidwell, K.M., Wu, T., Nahum-Shani, I., Almirall, D. (In progress) "Sample Size Considerations for the Analysis of Continuous Repeated-Measures Outcomes in Sequential Multiple-Assignment Randomized Trials."

Posters and Presentations



  • Seewald, N.J. "GITting Started with Reproducibility: An Introduction to git and knitr." Biostatistics Student Association Computing Workshop, University of Michigan. January 29, 2016. Invited. Resources
  • Seewald, N.J. "Getting Started with LaTeX." Biostatistics Brown Bag Seminar. Department of Biostatistics, University of Michigan. November 6, 2015. Invited. Resources
  • Seewald, N.J.; Almirall, D.; Kidwell, K.M. "Design, Analysis, and Sizing of Sequential Multiple Assignment Randomized Trials with Binary Outcomes." Graduate Student Statistical Topics Seminar Series. Department of Statistics, University of Michigan. September 24, 2015. Invited. Slides
  • Seewald, N.J.; Almirall, D. "An Introduction to Adaptive Interventions and SMARTs." Guest Lecture, SURVMETH 988: Advanced Seminar in Survey Methodology. Instructor: William Yeaton. Institute for Social Research, University of Michigan. June 24-25, 2015.
  • Nahum-Shani, I.; Seewald, N.J. "Getting SMART: Experimental Design and Analysis Methods for Developing Adaptive Interventions." University of California San Francisco. May 19, 2015.
  • Tolpadi, A.; Seewald, N.J. "LaTeX 101/201." Biostatistics Brown Bag Seminar. Department of Biostatistics, University of Michigan. December 4, 2015. Invited.


A sample size calculator for sequential, multiple-assignment, randomized trials with binary or continuous outcomes in which the primary aim is to compare two embedded dynamic treatment regimes.

Made in collaboration with Kelley M. Kidwell and Daniel Almirall.

Currently in beta. Implementation and/or methods are subject to change without notice.

MRT-SS Calculator

A sample size calculator for micro-randomized trials in which the primary aim is to detect the proximal effect of providing an intervention.

Made in collaboration with Ji Sun and Peng Liao.