The 2020 workshop will be held in Boulder, Colorado, March 2nd-6th, 2020, with John Hewitt and Matt Keller as Local Hosts, and Michael Neale serving as the Academic Director and Sarah Medland as Associate Director. The course is planned to include sessions on: causes of variation; biometrical genetics; OpenMx; regression, path analysis, matrix algebra, optimization; univariate twin analysis; ACE modeling; binary and ordinal data; multilevel modeling; between group heterogeneity; continuous heterogeneity, sex limitation and G x E interaction; multivariate models and genetic analysis; GREML; genomic SEM; developmental models; direction of causation modeling; polygenic risk scores; Mendelian Randomization; statistical power; responsible conduct of research. Hands-on analysis will be an integral part of the course.