Stats Chat

Team Ratings for Round 18

Not sure how I missed posting this one, but here it is for completeness.

The basic method is described on my Department home page.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 119 matches played, 94 of which were correctly predicted, a success rate of 79%.
Here are the predictions for last week’s games.

Predictions for Round 18

Here are the predictions for Round 18. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Delayed Games

The basic method is described on my Department home page.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 93 matches played, 61 of which were correctly predicted, a success rate of 65.6%.
Here are the predictions for last week’s games.

Predictions for Delayed Games

Here are the predictions for Delayed Games. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Round 19

The basic method is described on my Department home page.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 126 matches played, 99 of which were correctly predicted, a success rate of 78.6%.
Here are the predictions for last week’s games.

Predictions for Round 19

Here are the predictions for Round 19. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Week 4

The basic method is described on my Department home page.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 15 matches played, 7 of which were correctly predicted, a success rate of 46.7%.
Here are the predictions for last week’s games.

Predictions for Week 4

Here are the predictions for Week 4. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

It’s impressive that someone has done a poll in the US with only 1/3 of respondents wanting to abolish ICE. It was Third Way, who would like you to think of them as moderate.

When you look more closely you can see how it was done. The 34% figure is for “We need to abolish ICE and halt all immigration enforcement inside the country”.  These two policy changes are not especially closely linked — the US had immigration enforcement for a long time before creating ICE — and the first proposal, rather than the more extreme second one, is given the headline.

In August, the Guardian and the BBC reported a successful clinical trial of an “AI stethoscope”. I’ll note at the start that this isn’t ChatGPT, it’s the older deep neural network style of AI that works more predictably and consistently.

The BBC said

These reports were based on a presentation at a scientific conference, the European Society of Cardiology meeting. Yes, the trial was called TRICORDER.  “A good name is better than precious ointment”, as the Bible tells us.

There’s some reason to think the claims are plausible.  The most important of the abnormal heart rhythms is very obvious just by taking a pulse, and doctors listen for particular heart sounds as evidence of heart failure.  So, it could be true.  The “AI stethoscope” would still have to be better than a stethoscope together with natural intelligence, but that’s why you do the trial.  The trial randomly allocated half of the GP practices to use an AI stethoscope and the other half to business as usual.

Now we have the full research paper published in Lancet.  The abstract says

Intention-to-treat analysis found heart failure detection did not differ between groups (IRR 0·94 [95% CI 0·86–1·02]); with no difference in community-based or hospital-based diagnoses (p>0·05).

That is, there isn’t good evidence of a benefit from your doctor having an “AI stethoscope” and at least for heart failure detection there’s evidence against a meaningful benefit: the uncertainty interval tops out at a 2% increase.

It’s worth emphasising that the trial had already finished last August. All that differs is the analysis.   The analysis in the conference presentation was the “per protocol” comparison: comparing people who got an AI stethoscope examination with a curated set of controls who got at least one face-to-face consultation (but not necessarily a non-AI stethoscope). In fact, they couldn’t get enough information for data linkage on all the people who got an AI stethoscope examination, so the analysis only used half of them. The published paper also reports this analysis

Use declined over time, with clinicians citing workflow barriers to sustained use. In per-protocol analyses, adjusting for patient exposure to the AI-stethoscope, detection of heart failure (IRR 2·33 [95% CI 1·28–4·26]), atrial fibrillation (IRR 3·45 [2·24–5·32]), and VHD (IRR 1·92 [1·09–3·40]) was significantly increased in the intervention group.

So, doctors didn’t use the “AI stethoscope” much, but if you compare half of the people who did get AI stethoscoped with the same number of apparently similar people in the control group of the trial, you find big differences.  This difference could be a real benefit of the new device, but we no longer really have randomised evidence on that question; we’re relying on how similar the researchers could make the treatment and control groups.

It’s still worth publishing the data, and the researchers and Lancet get credit for putting the randomised-trial analysis first in the research paper. Lancet doesn’t really get much credit for posting the results as “AI-enabled stethoscopes show promise for improving diagnosis of cardiovascular conditions, UK trial finds”.

Team Ratings for Week 12

The basic method is described on my Department home page.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 85 matches played, 57 of which were correctly predicted, a success rate of 67.1%.
Here are the predictions for last week’s games.

Predictions for Week 12

Here are the predictions for Week 12. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Round 1

The basic method is described on my Department home page.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Predictions for Round 1

Here are the predictions for Round 1. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Week 3

The basic method is described on my Department home page.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 10 matches played, 5 of which were correctly predicted, a success rate of 50%.
Here are the predictions for last week’s games.

Predictions for Week 3

Here are the predictions for Week 3. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

• The “cancer mornings” paper now has an Editors Note “The editors are issuing this note to alert readers that concerns have been raised regarding inconsistencies between the registration record of this trial on clinicaltrials.gov and published version the study protocol, as well as with some of the findings in this study. Editorial action will be taken as appropriate once an investigation of the concerns is complete and all parties have been given an opportunity to respond in full.”  For people more familiar with politics, on the controversial/embattled/disgraced/former spectrum an editors note is somewhere near the controversial/embattled boundary.  In this example it’s a mixture of not believing the result is possible and some changes in the trial registration over time (as I mentioned).
• Various sources are enthusiastically repeating a claim that the Tesla Cybertruck is explodier than the notorious Ford Pinto was. The Cybertruck had had 5 fire fatalities in an estimated 34,438 vehicles, versus 27 in  3,173,491 vehicles for the Pinto.  Crudely, that’s a ratio of 17.  There’s obviously a lot of uncertainty, but a standard uncertainty interval for the relative risk goes from 5.8 to 41.  There are a few more caveats: first, one of the five Cybertruck deaths was deliberate. If we don’t count that one, the uncertainty interval is now 4 to 35. Second, the denominator isn’t that reliable for the Cybertruck.  Third, we don’t have any driving information — if the cybertrucks were driven more you might expect more fires.  Fourth, this is obviously a comparison selected after the fact, so it will be inflated and less reliable than the stats indicate.   As an illustration of the unreliability of this comparison there are claims for the Pinto that are more than an order of magnitude higher. Mother Jones, which reported the Pinto investigation, didn’t caveat the 27 deaths figure at all in its Cybertruck story.
• Marc Daalder has an interesting story at newsroom about changes in the NZ crime rate. Or, to be more precise, the NZ reported crime rate. Retail crime is one of the sectors where the numbers are driven by reporting — most robberies from shops aren’t reported because there’s no real benefit to doing so.  This is familiar in other crime areas — intimate partner violence for one — and in medical statistics, where diagnoses of, say, prostate cancer or lung cancer or melanoma are driven by testing.
• The Color Game: how well can you remember colours?
• Women’s clothing sizes: scrolly/visualisation “[at age 15] This means for the first time ever, most girls in their cohort will be able to find a size in the women’s clothing section. This will also likely be the last time this ever happens in their lives.”