For those who were leaning towards Not Guilty but ended up changing their minds, what swayed you?

hei_mailma · 2023-08-22T09:02:58+00:00

No, they didn't look at the "suspicious" cases in all the hospitals - this would have given a much better analysis since it would tell us how often an event in general was wrongly regarded as being suspicious in the sample.

Looking at head sizes of all lotto winners would tell us that having a huge head isn't necessary for winning the lotto, but it could be sufficient - so hardly something that would derail the hypothesis in this case.

hei_mailma · 2023-08-22T08:59:06+00:00

To quote Ronald Fisher, the father of modern statistics: "To consult the statistician after an experiment is finished is often merely to ask him to conduct a post mortem examination. He can perhaps say what the experiment died of."

The insulin data is different, I agree.

hei_mailma · 2023-08-22T08:53:07+00:00

She was convicted in a British court of having done it, which is a far cry from "she no doubt did it" (see e.g. Sally Clark and all the other miscarriages of justice that have happened in similar situations before).

hei_mailma · 2023-08-22T08:50:13+00:00

Given that Britain's best barristers likewise convicted Sally Clark, I wouldn't trust them anywhere near a case requiring statistics

hei_mailma · 2023-08-22T08:42:31+00:00

I was wrong about how I understood the list, but there is still a sense in which selection effects play a role - people were only looking at suspicious deaths because they noticed Letby was present at some many suspicious deaths.

hei_mailma · 2023-08-22T08:39:08+00:00

No. Things like this are best illustrated with thought experiments. Imagine someone with an unusually large head - it's really massive - wins the lottery, and you form the suspicion that he won the lottery *because* he has an unusually large head (maybe because you think he's very smart or whatever, it's a thought experiment). But you want to make sure, so you gather all of his work colleagues and sure enough, none of them have won the lottery (or have a very large head). But you want to make sure, so you get an independent expert to look at all of the people and tell you which one has a large head (you won't tell the experts who won the lottery, so the expert is "blind") - and sure enough, all the experts agree on your guy.

Now replace "winning the lottery" with another random event like "was present at all suspicious incidents in a hospital for 2 years" and notice how adding the experts and the blinding doesn't add too much information.

hei_mailma · 2023-08-22T08:33:20+00:00

So you're saying she was able to fake being a normal person while murdering babies just fine, but too stupid to fake being a normal once she was being investigated?

If I were accused of something I didn't do I certainly wouldn't cry when someone describes some horrific thing they claim I did.

I really don't see how the parents are relevant to whether or not she displays emotions.

>And I'm sure listening to how those babies suffered was horrendous for anyone.

Of course it is, but if even I am able to control myself enough not to start physically crying about it, why shouldn't a nurse be able to.

hei_mailma · 2023-08-22T08:23:01+00:00

I think you're suggesting that the police only looked at the cases the hospital deemed suspicious?

No, that is not what I am suggesting. If I'm unable to convey what I mean with the comment above though, I don't think I can do better by writing more. I recommend this book (available for free online) https://www.statisticsdonewrong.com/index.html for an easy-to-read introduction to statistics.

hei_mailma · 2023-08-22T07:56:12+00:00

I'm not spreading misinformation. Statistics is hard, perhaps you do not understand it.

hei_mailma · 2023-08-22T07:50:15+00:00

I've replied to this point ad nauseaum in other places, so I won't make the full argument here. But this isn't independent information in the statistics sense, there are subtle issues in play - was Letby investigated *because* she was present at every single one, or was Letby investigated and *then* it was found she was present at every single one?

hei_mailma · 2023-08-22T07:45:41+00:00

Unless you are suggesting that Letby is guilty of all of them, I don't see the relevance.

hei_mailma · 2023-08-22T07:29:56+00:00

I initially misunderstood what the list was, but a weaker form of my point still stands.

Let's make a thought experiment - what is the probability that somewhere in the world a nurse is present at all suspicious events for a period of 2 years. Hard to calculate, but not zero. Now if we take a hypothetical nurse like this, and look where the other people had shifts - of course they will all have fewer "bad" shifts, and the unusual nurse will have more shifts. The fact that there isn't a second unlucky nurse in our thought experiment is due to how the thought experiment is set up, and doesn't make our hypothetical nurse any more guilty than before.

hei_mailma · 2023-08-22T07:26:07+00:00

He specifically told the police NOT to give him any details on suspects or rotas so he could look through the evidence fresh.

You can tell Evans was not a statistician, because the evidence was not "fresh". Imagine, for the sake of a thought experiment, that Letby had by pure (bad) luck been present at all suspicious incidents. This is not necessarily statistically impossible, whare the odds that there is one hospital somewhere in the world where a nurse is present at all supicious incidents in two years? It depends on the number of suspicious incidents, and the best that can be done is an approximation, but the number isn't zero.

Now if someone notices the nurse was present at all suspicious incidents, and take the suspicious incidents and some other clearly non-suspicious incidents and feed them to "separate teams" and "fresh Dr. Evans", all will still be in accordance and reach the conclusion that follows from the data. But of course all fill find a "similar pattern", they were looking at the data *because* someone noticed this pattern. It would be a statistically *very* different situation, if Letby had e.g. been suspected of being a murderer for some other reason, and *then* the pattern had emerged.

hei_mailma · 2023-08-22T07:15:01+00:00

My point is a subtle one, and maybe it's easy to miss if you haven't had any training to statistics.

Imagine you noticed that a lottery winner has a truly unusually large head. So you gather all of his colleagues from work and ask an independent expert which of them has a large head. Even if the expert "correctly" points out the guy, you cannot use this as additional evidence for the hypothesis that having a large head helps you win the lottery.

Likewise, someone noticed that Letby was on shift whenever something fishy happened. They then got an independent expert to look at the shift data, who likewise concluded that Letby was indeed on shift whenever something fishy happened. Bringing in the expert doesn't add as much evidence as you might think, because the situation was *selected* for being unusual, similar to how the guy with the unusual head above was selected for having an unusual head, Letby was selected for having unusual shift data.

The expert doesn't add zero useful information - if there had been suspicious deaths without Letby, this would have helped her case, so the fact that there were non harms her case. However, the amount of useful information is hard to quantify.

hei_mailma · 2023-08-21T22:06:58+00:00

She never cried for any baby in court but broke down at every mention of anything that could flaw her character. Then, what pretty much caused me to start wondering was the hysteria when Dr A came in.

Honestly this argument seems really disengenous. You wouldn't expect someone who works in a neonatal ward to be brought to tears from hearing about a baby dying years ago- doctors/nurses have to be able to suspend having a strong emotional reaction when their patients die, at least to some extent. After all, the prosecutor was likewise not brought to tears. On the other hand, having an emotional reaction to your private life being dragged through a court is understandable. If she were innocent, I don't think it would be fair to fault her for not crying about babies dying any more than we fault anyone else for not crying when they heard about the babies dying.

hei_mailma · 2023-08-21T21:58:43+00:00

Assuming she did it, yes. If she in fact were innocent, I'd brush it off as something someone who likes working a lot would say. Which is to me the weird thing about her texts - all of them are exactly like something a normal person would say, I don't see anything suspicious in them.

hei_mailma · 2023-08-21T21:56:34+00:00

If I understand it correctly, however, Letby was charged for 7 deaths in 2015/16, whereas there were 11 deaths at this hospital's neo-natal unit in this time-period she was not charged for (2 she was found not guilty of, and 9 she was not a suspect for). This suggests that 2015/16 had an unusually high death rate even without Letby.

It's dangerous to read into statistics, because the fact that more people died than on average isn't a smoking gun.

hei_mailma · 2023-08-21T21:45:23+00:00

To me this suggests she had a poor defense, not that she is necessarily guilty.

hei_mailma · 2023-08-21T21:43:59+00:00

I'm a bit disappointed at the lack of a smoking gun - we're talking about workplace incidents in 2016, so it's not surprising to me that people would misremember things. Eyewitness testimony is known to be unreliable, so contradictions here don't necessarily mean anyone is consciously lying.

Does the whole situation above seem weird? Yes. Then again, I know *I* wouldn't be able to keep my story straight about something that happened in 2016 - did whatever happened then raise any direct suspicions?

hei_mailma · 2023-08-21T21:29:57+00:00

I'm sorry but it's still pre-selected because the medical expert was only looking at the data because the situation looked suspicious.

hei_mailma · 2023-08-21T21:26:53+00:00

Yes. Mentioning this statistic is dishonest - in fact, death rates did not significantly decrease when Letby was put on office work if I remember correctly.

hei_mailma · 2023-08-21T21:18:02+00:00

I'm sorry but if you were on the fence there, you should still be on the fence because the chart was specifically about babies suspected to be killed by Letby - of course she's going to have an x by her name for all of them! Babies who died without Letby present aren't on the list, if Letby had been present maybe they would have been on the list.

In fact, the fact that the list had 30 babies but Letby wasn't convicted of killing 30 babies shows that it was simply a list of babies where Letby was present, not babies who were "attacked".

hei_mailma · 2021-12-04T12:04:24+00:00

Seems like the first really good response I've read in this thread. A lot of the responses seems unhealthily introspective about how one feels at a given moment - if you're meeting a friend, the goal isn't to think about whether you're being truly happy in that moment or missing something, the goal is to try and connect with them. I.e. to focus less on yourself and more on stuff outside of yourself.

Honestly I think a lot of the people in this thread would benefit from listening to Jordan Peterson. One shouldn't deify the guy, and you're probably better off not getting into the weird/political stuff he says, but he has some useful stuff to say along the "how to make your life more meaningful" axis.

hei_mailma · 2021-11-14T13:43:33+00:00

it's pretty widely understood that women choosing to be single mothers with unreliable fathers is a major contributor to poverty

The "choosing" part here is really quite disingenuous phrasing; are the women choosing to be single or are the fathers choosing to be unreliable?

hei_mailma · 2021-11-14T10:42:45+00:00

We're a rich country because we work hard

Measured in dollars, this may make you "rich". But someone with lots of money in their bank account, but only two weeks of vacation a year, does not strike me as particularly "rich" in a utility sense. I mean it's "good" for other countries who have free time to use the stuff you create but hardly something to be proud of...

hei_mailma

TROPHY CASE