The Center for Biological Risk organized a workshop on quantitative risk assessment on May 8 – May 10, 2018. Chris Field, a postdoctoral fellow at the National Socio-Environmental Synthesis Center, led workshop participants through lectures, discussion, and hands-on analysis of biological risks. The session covered current and emerging methods for quantifying risk across a range of scales, including both Bayesian and frequentist approaches, as well as software programs available for analyses.