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More generally, the words for the non-metric units are often much more convenient than the words for the metric ones. I think this effect is much stronger than any difference in convenience of the actual sizes of the units.

I think it's the main reason why many of the the non-metric units are still more popular for everyday use than the metric ones in the UK, even though we've all learned metric at school for the last forty years or so.

It's slightly disconcerting to imagine some of the writing coming from the pen of an Anglican deacon.

The useful advice is in the first 5000 words of the essay, most importantly in the examples of bad writing. The 100 words or so of 'rules' are just a summary at the end.

This kind of teaching is common in other subjects. For example, in a Go textbook it's not rare to see a chapter containing a number of examples and a purported 'rule' to cover them, where the rule as stated is broken all the time in professional play. It would be a mistake to conclude that the author isn't a strong player, or that the chapter doesn't contain helpful advice. The 'rule' is just a way to describe a group of related examples.

I think it's better to think of the 'rules' in Orwell's essay more like mnemonics for what he's said earlier, rather than instructions to be followed on their own.

I don't find it off-putting, but it does make me feel I'm reading Lewis Carrol.

Priors don't come into it. The expert was presenting likelihood ratios directly (though in an obscure form of words).

That isn't what was going on in this case. The expert wasn't presenting statistics to the jury (apparently that's already forbidden).

The good news from this case (well, it's news to me) is that the UK forensic science service both understands the statistics and has sensible written procedures for using them, which some of the examiners follow. But they then have to turn the likelihood ratio into a rather unhelpful form of words like 'moderately strong scientific support' (not to be confused with 'moderate scientific support', which is weaker), because bringing the likelihood ratios into court is forbidden.

(Bayes' Theorem itself doesn't really come into this case.)

This isn't quite "a judge has ruled that [Bayes' theorem] can no longer be used", but I don't think it's good.

The judges decided that using a formula to calculate likelihood isn't allowed in cases where the numbers plugged into the formula are themselves uncertain (paragraph 86), and using conservative figures apparently doesn't help.

Paragraph 90 says that it's already established law that Bayes' theorem and likelihood ratios "should not be used", but I think it means "shouldn't be talked about in front of the jury".

Paragraph 91 says explicitly that the court wasn't deciding how (or whether) Bayes' Theorem and likelihood ratios can be used in cases where the numbers plugged into the formula aren't themselves very uncertain.

In paragraph 95, the judges decide that (when matching footprints) it's OK for an expert to stare at the data, come up with a feeling about the strength of the evidence, and express that in words, while it's not OK for the same expert to do a pencil-and-paper calculation and present the result in similar words.

I think part of the point is that when the expert is cross-examined, the jury will react differently if she says "this evidence is strong because I've got lots of experience and it feels strong to me", rather than "this evidence is strong because I looked up all the frequencies and did the appropriate calculation".

I do get the impression that the approach of multiplying likelihood ratios is being treated as a controversial scientific process (as if it were, say, a chemical process that purported to detect blood), and one which is already frowned upon. Eg paras 46, 108 iii).

Thanks for the link.

I think paragraphs 80 to 86 are the key paragraphs.

They're declaring that using a formula isn't allowed in cases where the numbers plugged into the formula are themselves uncertain.

But in this case, where there was uncertainty in the underlying data the expert tried to take a conservative figure. The judges don't seem to think that helps, but they don't say why. In particular, para 108 iv) seems rather wrongheaded for this reason.

(It looks like one of the main reasons they overturned the original judgement was that the arguments in court ended up leaving the jury hearing less conservative estimates of the underlying figures than the ones the expert used (paras 103 and 108). That seems like a poor advertisement for the practice of keeping explicit calculations away from the jury.)

Well, I'm in the UK, and there's no law against using IQ-style tests for job applicants here. Is that really the case in the US? (I assume the "You're a terrorist" bit was hyperbole.)

Employers here still often ask for apparently-irrelevant degrees. But admission to university here isn't noticeably based on 'generic' tests like the SAT; it's mostly done on the grades from subject-specific exams. So I doubt employers are treating the degrees as a proxy for SAT-style testing.

In your third speculation, I think the first and second category have got swapped round.

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