← All chapters Chapter 17

Quantitative Considerations

A single number whose uncertainty is not large but unknown.

The Boolean structure turns basic-event rates into a PMHF, and the standard sets limits per ASIL — but the result must be treated with utmost caution, because the variance of its catalog-and-mission-profile inputs cannot be stated and so cannot be propagated. The number's honest job is ranking alternatives; what decides whether a product is safe is the qualitative structure, not a decimal place.