Check Our Math
What are the odds that a jury, having found for the plaintiff in a typical occupational cancer case, got it right (which is to say, got to the truth)?
Assume the following:
a) The odds that a jury will correctly attribute the cancer to the defendant when, in fact, it was an occupationally-induced cancer is 75% (i.e. the chance of a false negative, that plaintiff loses when she shouldn't, is only 25%)
b) The odds that a jury will find for the defendant when the defendant had nothing to do with plaintiff's cancer is 75% (i.e. the chance of a false positive, that a defendant will be held liable when it had nothing to do with plaintiff's cancer, is only 25%).
c) The odds that a given cancer case is occupationally related is 10% (that's 2.5x the typical estimate of 4% by Sir Richard Doll (of cigarettes-cause-lung-cancer fame) but let's go with it).
In such cases, when the jury has found for the plaintiff, they only get it right 1 in 4 times. Why? Because the vast majority of cancer cases aren't occupationally related. The false positives pile up. It's like the lesson we've learned with PSA tests and mammograms. Imagine 1000 cancer cases. 100 are occupational (using our plaintiff-friendly assumption above). 75 of those 100 will be detected by the jury but of the remaining 900 non-occupational cancer 225 (25%) will be wrongly assumed to have been occupational. That means that the odds that a given verdict in an occupational cancer case is the just one, the one that got it right, is 75/(225 + 75) = .25 = 25%.
Play with the numbers and assume that juries identify the deserving plaintiff 51% of the time and absolve the innocent defendant 51% of the time and use Doll's 4% figure for the number of occupationally related cancers. You'll find that for any given verdict under such a scenario there's less than a 1 in 20 chance that the defendant really caused plaintiff's cancer.
To move the number up to a point where we can be confident of the verdict, while sticking to a "featherweight", 51% more-likely-than-not standard for finding a defendant at fault, we have to assume that most cancers are caused by working. That assumption was popular several decades ago but it's no longer one that has anything to do with reality. Nowadays the math really only works for one type of cancer - mesothelioma.
