In 2016, the U.S. Department of Homeland Security, Office of Policy– Strategy, Plans, Analysis, and Risk, asked the RAND National Defense Research Institute to design and implement a risk identification and characterization of natural and manmade threats and hazards to identify the greatest risks to homeland security and support prioritization of DHS mission elements as part of DHS strategic planning processes. This report describes the risk assessment methodology RAND researchers devel- oped to address these goals.
https://www.rand.org/content/dam/rand/pubs/research_reports/RR2100/RR2140/RAND_RR2140.pdf