Consistent with
Consistent with
/kənˈsɪstᵊnt wɪð/ (n.)
A phrase which sounds more damning that it has any right to be. JC has a bicycle. This is consistent with his winning the Tour de France— try winning it if you don’t have a bicycle! — but it does not make him any more likely to do it.
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Crime & Punishment
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Poor old Joe died that night
Under the desert moon
Well, spoil the child, spare the rod
Don’t ever mess with the fist of God.
- —The Johnnys, Injun Joe (1985)
Forensic pathology is inherently multivariate. Many things cause collapse and death. It doesn’t matter so much that a collapse is consistent with a given cause, but that it is inconsistent with any other.
“Consistency” is an attestation of correlation that is often taken by people who should know better, to be one of causation. When a stabbed body is found in a room of ten thousand knife-wielding men, then a chap holding a knife is, yes, consistent with being a murderer, but it is still highly unlikely to be predictive of it.
Your job, Inspector Squirrel, should you be called to the scene of a stabbing, is not just finding a man with a knife. You will need to do that, but you will need to rule the others out, too. This you may do by exclusion, Sherlock Holmes style, but that only really works well in an Arthur Conan Doyle story
The far better way of doing it is finding some positive evidence that this chap is the murderer. A witness is a good start. Or some good circumstantial evidence implicating this fellow,
Expert evidence that, for example, “blotched, mottled skin is consistent with air embolus”[1] is of little “probative value” unless blotched, mottled skin is not consistent with any other condition that might be prevalent or, for that matter, any non-medical explanation.
If the evidence is also “consistent with” a range of other common, frequently observed alternatives as well as the extremely rare and damning one that propels the prosecution case, then that base rate is important: the prior probability that this is a case of air embolus remains low.
Likewise, “a predictor of”. Take this sage advice from that peddler of web-ready fatuities, Adam Grant:
A neglected predictor of success and happiness is doing chores from an early age.
Perhaps the sort of parents who raise successful children are the sort that make their children do the washing up. It might not seem so new, or relatable, and Professor Grant might not harvest quite so many likes were he to recast is wisdom like so:
Spare the rod, spoil the child.
Don’t ever mess with the fist of God, friends.
See also
References
- ↑ One of the critical planks of the Crown’s case against Lucy Letby.