- Untestable Faults – UT
- Unused – UU
- Tied – TI
- Blocked – BL
- Redundant – RE
- Testable Faults
- Detected – DT
- det_simulation – DS (faults detected when the tool performs fault simulation)
- det_implication – DI (faults detected when the tool performs learning analysis)
- det_robust
- det_functional
- Posdet – PD
- posdet-testable – PT (Can be detected by increasing the test generator abort limit)
- posdet-untestable – PU
- ATPG Untestable – AU (Cannot be detected by increasing the test generator abort limit)
- Undetected – UD
- Uncontrolled – UC
- Unobserved – UO
- Detected – DT