A quantitative analysis identifies the likelihood of occurrence of the top event and of each minimal cut set (if qualitative analysis is also performed). To perform quantitative analysis, a failure probability, failure rate, repair rate, or failure frequency must first be entered in the calculation properties for each lowest-level event. When minimal cut sets are calculated, the unavailability and unreliability of the system can be computed. These measures, rather than availability and reliability, are computed because fault trees are organized around failures rather than successes.