#### Comment Preferences

• ##### Probabilities are additive in these cases(0+ / 0-)

If there's a 1% risk per year at each of 26 points on a pipeline, the probability of at least one disaster is 26% per year.

• ##### That is simplistic(0+ / 0-)

Because of the possibility of correlation - that is, if your processes failed on one weld, they are more likely to have failed on the others.

Common cause failures are the bane of failure analysts, playing a role similar to that of demons in medieval theology.

Purity is for primaries; in the general, our worst are better than their best.

[ Parent ]

• ##### Yes(1+ / 0-)
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blue aardvark

...and even if they are independent, it's simplistic, as it's multiplicative. If the probability of making a mistake on entering a single digit in a long string is X, the probability of getting the whole string right is 1 minus X to the Nth, where N is the number of digits, I believe.  It gets dangerously low even if you start with a 1% error rate, as N increases.

I'm from the Elizabeth Warren wing of the Democratic Party

[ Parent ]

• ##### No minus, sorry. (1+ / 0-)
Recommended by:
blue aardvark

I'm from the Elizabeth Warren wing of the Democratic Party

[ Parent ]

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