Bulus, M. & Dong, N. (2019). cosa: Bound Constrained Optimal Sample Size Allocation. R package version 2.1.0.

      • Implements bound constrained optimization of sample sizes in power analysis of multilevel regression discontinuity designs (MRDDs) and multilevel randomized trials (MRTs) with continuous outcomes under bound constrained optimal sample size allocation framework (BCOSSA). The description of the method and tutorial is available at

Bulus, M., Dong, N., Kelcey, B., & Spybrook, J. (2019). PowerUpR: Power Analysis Tools for Multilevel Randomized Experiments. R package version 1.1.0.

      • Includes tools to calculate statistical power, minimum detectable effect size (MDES), MDES difference (MDESD), and minimum required sample size for various multilevel randomized experiments with continuous outcomes. Some of the functions can assist with planning two- and three-level cluster-randomized trials (CRTs) sensitive to multilevel moderation and mediation (2-1-1, 2-2-1, 3-3-1, 3-2-1, and 3-1-1).

Bulus, M. & Bonifay, W. (2018). irtDemo: Item Response Theory Demo Collection. R package version 0.1.4.

      • Includes a collection of shiny applications to demonstrate or to explore fundamental item response theory (IRT) concepts such as estimation, scoring, and multidimensional IRT models.