[Editor's Note: In the online version of this article, we have updated the discussion of the Quantitative Criticality Analysis calculation method.]
Criticality Analysis is another method of risk assessment that can be used in conjunction with an FMEA. MIL-STD-1629A describes the requirements for two types of failure modes, effects and criticality analysis (FMECA): quantitative and qualitative. To perform a quantitative criticality analysis, the analysis team must:
A qualitative criticality analysis, as described in the military standard, is similar to the Risk Priority Number (RPN) method. The analysts use predefined rating scales to rate the likelihood of occurrence for each failure mode and the severity of the potential effects of failure. However, the probability of prior detection is not considered. A matrix with severity on the horizontal and occurrence on the vertical axis can be used to compare failure modes from this analysis.