The probability of a wrong conformity decision for a single item, computed from its measured value, the measurement uncertainty and the tolerance limits. A reading in the middle of the tolerance carries almost no risk, while a reading sitting right on a limit has close to a 50 % chance of being on the wrong side. It contrasts with global risk, which averages false-accept or false-reject probability over a whole population before anything is measured.
Specific risk on that last reading is 18 percent, too close to the limit to pass without a re-measure.
Also heard as
- conditional risk
- bench-level risk
Do not mix it up with
- PFA: PFA is often quoted as a global, population-level figure; specific risk is for the one item and reading in front of you.
Related terms
PFA
Probability of false accept, the chance that a nonconforming item is measured and passed as good.
Guard band
A margin that pulls acceptance limits inside the tolerance limits to cut the risk of passing nonconforming items.
Decision rule
The agreed method for factoring measurement uncertainty into a pass or fail call against a spec.
Simple acceptance
A decision rule that passes any item whose measured value lies inside the tolerance, leaving uncertainty out of the call.