2021iii24, Wednesday: Does it add up?

The slipperiness of statistics, and why us advocates need to learn to love numbers. Plus: wise words from the US on design.

Short thought: I have a problem with numbers: I like them.

Don’t get me wrong. I’m not a mathematician. My formal maths education stopped at A-level, decades ago, and has only restarted recently as I’ve sought to help my daughter with her GCSE maths studies through lockdown.

But numbers don’t scare me, and there’s an ethereal beauty to maths which always appeals. Which, I think, is generally a good attitude in an advocate.

Still, that’s the problem. I sometimes find it hard to understand just how daunting maths – and particularly statistics, perhaps – can be to many people. To be clear: that’s a failure of empathy on my part, not any failing on theirs.

Why “particularly statistics”? Because, I think, they can often defeat common sense. And while Darryll Huff’s seminal book “How to lie with statistics” overdoes it (Huff later became a key smokescreen for Big Tobacco, unfortunately), the fact remains that using stats to obfuscate instead of illuminate is an old and well-used trick because it works.

(Chart crime is a subset of lying with statistics, or perhaps an overlapping circle on a Venn diagram. Because often chart crime arises from negligence, not malice. FT Alphaville’s Axes of Evil series, from which the above illustration is drawn, is an excellent set of examples.)

A great illustration of the “common sense is wrong” problem is highlighted in a piece by a Conservative MP, Anthony Browne. (I don’t usually link to pieces by Tory MPs on ConservativeHome. But this, despite the clickbait headline about government policy, is really good.) Anthony says his constituents are up in arms because their kids are getting sent home from school on positive LFD Covid tests, and kept away even when they have a negative PCR test thereafter. Surely the PCR tests are gold standard? This can’t be right.

Well, yes it can, says Anthony. And he’s spot on. The issue arises because of the counter-intuitive way that false positives (getting a yes when it should be a no) and false negatives (the other way round) interact with large populations with a relatively low incidence of what you’re testing for.

Put simply:

  • Imagine a million kids, and 0.5% of them – 1 in 200, or 5,000 – have the Bug.
  • A positive LFD test is almost always right (only 0.03% false positives – only a tiny fraction of people told they have the Bug will prove not to have it), but a negative test is much more unreliable (49.9% false negatives – in other words, if you’ve got the Bug there’s a 50/50 chance the test will say you haven’t).
  • A positive PCR test is basically always right. But 5.2% of people with the Bug will get a negative result nonetheless.
  • Of the million kids (remember: about 995,000 are fine, about 5,000 have the Bug), the LFD will flag 2,500 of the kids with the Bug. (Yes, the other 2,500 won’t get flagged. But that’s a different problem…) It’ll also flag about 300 kids who are clean. Oops.
  • So 2,800 kids get sent home, along with their close contacts. Assume all 2,800 then have a PCR test.
  • The zero-false-positive thing means all 300 of the mistakes will get picked up. Yay! Back to school for them and their classmates?
  • Er… no. Here’s the problem. That 1-in-20 false negative rate means that about 125 or so of the 2,500 kids who DO have the bug will get a negative result as well.
  • So of the 425-odd kids whose PCR looks like they should be allowed back into school, a third of them are actually Bugged.

This, says Anthony, is why the government is right to disallow immediate return after a negative PCR. And I see his point. The stats are right, if utterly counter-intuitive. 

What’s this got to do with advocacy? Well, so much of our work involves numbers. In crime, it’s DNA tests. In personal injury, it’s causation for some kinds of illness and injury. In commercial matters, we spend our lives poring over company accounts and arguing over experts who tell us what’s likely and what’s not. And an awareness of Bayesian reasoning can be a huge help when assessing whose story stacks up.

And if we don’t speak numbers, how can we possibly ensure our clients’ cases are properly put?

This point isn’t new, and the profession knows it. Working with the Royal Statistical Society, a couple of years ago it put together a guide for advocates on statistics and probability. It’s brilliant. Download it, and keep it as a ready reference. And – as I’m trying to do – find ways of illustrating probability that are transparent to people for whom this just isn’t straightforward, or that take into account the times when statistics boggle the common-sense mind.

One final word on Anthony’s piece, though. He rightly points out that these numbers change as the incidence drops. The false-negative rate in the above example, for instance, falls to less than 10% once the incidence of the Bug is down to 1 in 1,000. 

But his overall point – that government policy is backed up by the numbers – has one big hole, it seems to me. As we noted, the false negative rate for LFDs is 50%. So even on our example, that’s 2,500 kids WITH the Bug who are in school, in the honest but mistaken belief that they’re no risk to anyone.

In other words, the reliance on LFDs for school testing is a false comfort – a form of pandemic theatre (akin to the security theatre that made air travel such a pain before it was wiped out by the Bug). And compared to that, quibbling over the 125 kids to whom the PCR has wrongly given the all-clear seems a bit pointless. 

(An invitation: I like numbers, but I’m not a statistician. If I’ve got any of the above wrong – particularly the final bit about the 2.5k kids innocently swanning around leaking Bug everywhere – let me know and I’ll correct myself.)

Someone is right on the internet: As a follow-up on the font conversation on Monday, I’ve always been a fan of style guides. Not the ghastly prescriptive grammatical guides (Strunk and White, I’m looking at you); I mean the guides some publications craft to help their writers keep things consistent. Good examples come from the Guardian and the Economist.

These, of course, deal with words themselves, not the typography in which they appear. But a good friend (thanks, Ian) points to a guide published by the Securities and Exchange Commission in the US. It’s aimed at people creating investor notifications, for instance about listings, and spends a lot of time suggesting clear language (and is really good on that). But there’s also a chapter (chapter 7) dealing with design, which says wise and interesting things about fonts. Worth a look.

It also makes some worthwhile and entirely true points about layout: for instance, that a ragged right-hand margin is far more readable than a justified one. I’d love to adopt that one in my legal drafting. However, I suspect that if I hand in a Particulars of Claim, or a skeleton argument, with a ragged margin, I’m likely to get into even more trouble than I will by continuing to use Garamond. Baby steps…

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2021iii22, Monday: font (mis)judgments.

Like many ex-hacks, I take fonts seriously. Clearly US judges don’t – or rather, they do for the wrong reasons. More fool them.

Short thought: It may be just my background as a reporter, but fonts and layout matter to me. A well-chosen typeface, apt for the task at hand, and a design which leads the eye to where it needs to go and includes enough space for the text to breathe, aren’t afterthoughts. They’re integral to the process of respecting the reader’s attention, and maximising the chance that the words will get past the pupil and into the brain.

None of that changes when you’re an advocate instead of a journalist. The more so, perhaps: obviously a nice design isn’t going to save a hopeless case or slipshod drafting, but all things being equal a pleading or skeleton which makes the tribunal’s life easier can’t hurt, and is highly likely to help.

I’m staggered, therefore, when I discover friends and colleagues who don’t have templates that do the hard work for them, routing around Microsoft Word’s disastrously unpredictable list settings and ensuring that headings, subheadings, and cascading numbering all work consistently and well.

I started developing one about three months into pupillage, with styles for every type of paragraph and heading I needed. I update it every few months. It stands me in good stead. It does the critical job of making sure I only need to worry about the words.

The one thing I never settle on, though, is a font. Not for me Times New Roman; I know it’s traditional, but sweet Jesus it’s boring, ugly and not particularly pleasant to read. Calibri or Cambria? No. Helvetica? A little too grotesque. Arial? Don’t even. Seriously.

I waver between Liberation Serif (for when a serif font is absolutely necessary) and Gill Sans (my BBC background leaves me with a huge soft spot for this). Both are readable, clear, understated and – critically – reasonably compact.

(This is why, sadly, I have to avoid Optima. It’s always been a clear favourite of mine, hinting at serifs and exploiting their readability without actually quite displaying them. But it’s just too big, so even a relatively short skeleton starts looking like something of a novella to a time-pressed judge.)

Sometimes, though, I return to an early love: Garamond. Not only is it a thing of beauty, harking back to the early Apple days (when it was the standard house font for printed materials). It’s also startlingly compact. When you’re short of space and there’s a page limit, Garamond can squeeze in about 15% more words.

Unfortunately, everyone knows this. Including, apparently now, the DC Circuit Court of Appeals in the USA, which has now explicitly said it wants Century or TNR, and specifically doesn’t want Garamond.

Tasteless beggars. Shame on ‘em. Not least for the utter monstrosity of a font they used to issue the edict.

(This is not unduly to critique my friends who don’t see it that way – I’m looking at you, Daniel. But there’s been a nice little twitter-spat brewing – nicely good-natured despite the critically important nature of the subject matter – among UK barristers on this. It seems to have died down, so obviously one shouldn’t pitch in and re-ignite it. Obviously.)

Someone is right, and wonderfully generous, on the internet: Anyone involved in civil litigation needs to understand Denton.

For those fortunate enough to be uninitiated: more often than any sane person would like, things go wrong. Deadlines are missed. Orders or rules are broken. And sanctions are applied by the Court.

When they are, rule 3.9 of the Civil Procedure Rules allows a party to apply for relief from those sanctions – to have permission to file a late pleading, say, or to use an expert witness. But the rule is very brief. How the Courts will apply it in practice is the subject of an ever-expanding body of authority, arising primarily from the case of Denton v TH White [2014] EWCA Civ 906 which set a three-stage test: Was the breach serious or significant? Was there a good reason for it? What, in the light of all the circumstances, is the just thing to do?

Clearly, applying this is – as we lawyers say – an intensely fact-specific exercise. Every situation is different. But that body of authority can help you work out where your client stands – and maximise the odds of getting the result you want.

How, though, to keep track of it? In an act of wonderful generosity, Dr Rachel Segal of St John’s Chambers in Bristol not only does so, but regularly shares the results in a PDF, currently more than 200 pages long. If you’re seeking relief from sanctions, or opposing it, you can’t do better than to start with Rachel’s document, current as of last month.

I was reminded of Rachel’s magnum opus by an equally superb resource, which I must have mentioned before: Gordon Exall‘s Civil Litigation Brief website. How the man finds the time to do any actual billed work is beyond me, but this site is an absolute godsend, particularly for examples of how the courts deal with knotty procedural issues.

(If you’d like to read more like this, and would prefer it simply landing in your inbox three or so times a week, please go ahead and subscribe at https://remoteaccessbar.substack.com/.)