There's a hierarchy of severity that's expected in industrial accidents, as I've recently learned running across a reference to the concept. The work was done a long time ago -- ~1930s - 1950s, and I think the earlier part of that period. It's used fairly heavily in the insurance industry still, from what I understand.

(I'm being a little vague because I can't immediately turn up that reference, I'll take a look for it.)

The upshot is that if you've got a base incident / accident / failure rate, you can predict with a fairly high degree of accuracy the likelihood of major accidents -- fatalities, major injuries, or catastrophic to plant and equipment.

(Now to see if I can find that.)

Here: H. W. Heinrich, Industrial accident prevention: a scientific approach (1959)

The publication date is later than I'd thought, but the data were collected much earlier -- 1931.

https://www.worldcat.org/title/industrial-accident-preventio...

Which I'd originally turned up ... through a NASA accidents presentation: http://www.hq.nasa.gov/office/codeq/accident/accident.pdf