How functional safety managers construct failure modes, effects, and diagnostic analysis (FMEDA) sheets to prove Single-Point Fault Metric (SPFM > 99%) and Latent Fault Metric (LFM > 90%).
ISO 26262 ASIL-D mandates an SPFM score of at least 99%. The formula divides safe faults plus detected dangerous faults by the total failure rate of the system: `SPFM = 1 - (Sum(Dangerous Unfiltered Failures) / Sum(Total Failures))`. To reach 99%, an automated hardware memory parity check is insufficient (typically 60-90% coverage); silicon must deploy hardware ECC with background scrubbing and dual-core lockstep to achieve 99.5% diagnostic coverage.