Malcolm Barrett is an epidemiologist and open-source software developer. After receiving his Ph.D. in epidemiology from the University of Southern California, he worked as a data scientist at Apple and Posit. His work has focused on causal inference methodology and software development, including many R packages for causal inference. Collectively, open-source tools he has authored have millions of downloads. Malcolm also teaches workshops and courses in R, software development, and causal inference.