From the abstract: "Qualitative risk ranking systems are often used to assess homeland security threats due to their simplicity and intuitive nature. However, their appropriate use is limited by subtle common underlying difficulties that render them inconsistent with quantitative risk assessments. A better way to assess homeland security threats is to use simple fully quantitative risk models coupled with managerial review and judgment."
2015 by the author(s). Posted here with permission. Documents are for personal use only and not for commercial profit.
Homeland Security Affairs Journal: http://www.hsaj.org/
Homeland Security Affairs (February 2015), v.11, article 3