Clinical trials prospectively assign participants to two or more interventions and prospectively measure outcomes on the participants. Clinical trials are the gold standard for studying the effectiveness of interventions and are usually required for regulatory approval. Several members of the department are involved in developing methods for design, analysis, and interpretation of clinical trials. For example, Dr. Schmid and others have published extensively on meta-analysis for clinical trials and Dr. Schmid is a leader in the developments of methods for and applications of N-of-1 trials which are single person multiple cross-over studies. Dr. Steingrimsson works on developing machine learning methods for data-driven discovery of subgroups with enhanced treatment effects. ECOG-ACRIN has carried out large trials comparing different screening modalities in cancer.