Miscarriages of justice
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The JC Sounds Off™
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Standard of proof
Beyond reasonable doubt is a very high standard. This is not just more likely than not: there has to be no room for doubt about it. The jury must be “sure”. This means a few things:
- The defendant does not need to do much to displace it. The defendant definitely does not need to persuade you she is innocent. Even if you think, “well, she probably did it but, you know, I just can’t be sure —” and the defendant should be acquitted.
- This means every plausible alternative explanation must be ruled out. If there is a plausible, mutually exclusive alternative explanation, even if it seems quite unlikely, and even if you still think the defendant probably did it, then you cannot be sure the defendant did it. This is one of those logical things.
- By the same token, you don’t have to rule out absurd alternative explanations. Aliens, extraordinary consequences, twenty-five standard deviation events, things like that
What is your evidence?
Direct evidence
Independent
It is satisfiable easily enough where there is direct independent evidence — from a third party with no interest “no dog in the fight” who directly witnessed what was going on. The main avenue of enquiry here is
- Ruling out any grounds that might taint the witness’ independence. If it turns out the witness does have a dog in the fight, it must be relegated to a non-independent direct witness.
- Ruling out any grounds for malice, unreliability, though they tend to fold into non-independence.
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Ensuring that the witness did indeed witness what she thought she witnessed, could not have been mistaken, drawn the wrong conclusion and so on.
Non-independent
This is eye-witness evidence from someone who claims to have seen the defendant committing the crime but who does have skin in the game — someone who is motivated to say the defendant was guilty, or who was naturally incentivised to construct a narrative in which the defendant was the guilty party.
Classic case: the victim of the alleged crime.
But also, a person who might be implicated in an alternative explanation, either as a criminal herself (that is, an alternative defendant) or otherwise perceived as falling short of an expected duty should that alternative explanation be preferred. The administrator of a failing hospital with an unusually high mortality rate amongst infants, for example, or a person who would otherwise be found to be in a bad light by alternative evidence.
Clearly, here we should take this evidence with a grain of salt, but it has some probative value — just because I was married to the victim doesn’t mean I didn’t see what I said I saw).
Circumstantial evidence
Evidence that relies on an inference to connect it to a conclusion of fact. This may be fingerprints, evidence of physical presence, prior convictions, modus operandi. Where there is no direct evidence, then the circumstantial evidence has to be compelling.
Modus operandi
For multiple offences: how consistent is the modus operandi? If you don’t have eye-witness evidence there needs to be something suggesting the same motivating cause was behind all the offences, and mere “proximity to the scene of the crime” is a loose connection indeed. The more “crimes” there are the more germane will be the similarity. (Clearly, with a single crime, there is no possibility of similarity!)
Beware the “well, lookee here” theory, where there is no forensic evidence tying the defendant to the crime, and presence/opportunity is the only one.
- Lucy Letby: Not consistent MO: multiple kinds: insulin, air embolism, overfeeding, knocking out tubes. Sounds like you are fitting the action to the outcome and not vice versa. If you discover 15 people all of whom have been shot between the eyes with the same calibre rifle in the same neighbourhood, there is a starting presumption it the same cause did for them all.
Understanding probabilities