An important question in the planning stage of scientific empirical research is whether the chosen design is the most efficient for the objectives of the study. Design efficiency is related to precision of the estimators of model parameters in a statistical model and the power of statistical tests. Increasing power and precision can be achieved by increasing sample size or by using a more efficient design. For instance, researcher planning a longitudinal trial should determine whether to choose a design with few subjects and measure them often during the course of the trial, or to choose a design with many subjects and to measure them less frequently.
Optimal design is a field of statistics that enables to design trials such that efficient estimates are achieved while minimizing study costs. This symposium shows recent advances in optimal design and power analysis in item response theory models, simple randomized trials with survival endpoints and cluster randomized trials.