I am not all that passionate about how many categories go into a severity rating. Certainly there isn't a single perfect or optimal number that fits everyone's needs. for me it's not whether or not it's easy to use 10 different categories, it's more about the value that more categories will give us. does it actually help us get to preventing and mitigating Problems? Will a 9 drive a different action than a 10?
Unlike Severity I am passionate about the whole occurrence rating. SXO is still bad math...
Unlike Severity I am passionate about the whole occurrence rating. SXO is still bad math...
Sometimes ranking systems with ten Severity rankings may drive different Recommended Actions than a system with nine Severity rankings.
The number of S, O, and D rankings is determined by the higher level customer FMEA. If the rankings are not the same it is more difficult to evaluate the risk of the higher level FMEA be it a simple system, sub-system or system level.