"Understanding Statistics in Medicine" is a companion volume to Tom and Michelle's "How to Report Statistics in Medicine," which is a comprehensive set of guidelines for documenting research and statistical methods in the medical literature. Understanding Statistics reflects Tom and Donna's separate experience in teaching the topics for many years, as well as the course on statistical reporting they teach on the University of Chicago's Medical Writing and Editing Program. Understanding statistics explains in more detail the reasoning behind the guidelines in How to Report Statistics.