Most fields require very high probabilities of safety, even when the stakes are much lower than the extinction of humanity.[1] Here are a few examples with risk thresholds expressed in Log Odds (base 10).
Intro to Log Odds
Instead of writing probabilities like 0.9999 which is hard to read, I'll use log odds.
So LogOdds
Conversion Trick: rounding LogOdds towards zero[2] roughly corresponds to the number of nines/zeros after the dot in the probability. Conveniently, the complementary probability in log space is just negative. LogOddsLogOdds(p)
Target Reliability Table (excluding earthquake, tsunami, and extraordinary events) Annual probability of various types of failure.
sudden, widespread progression of damage
| Types of Failure | Risk Categories | |||
| I[4] | II[5] | III[6] | IV[7] | |
| -3.90 | -4.52 | -4.90 | -5.30 | |
| -4.52 | -5.30 | -5.70 | -6.15 | |
| -5.30 | -6.15 | -6.60 | -7.00 | |
Lifetime Reliability Target ()
LogOdds: -3.63... (read 929 more words →)
