Stats Chat

Team Ratings for Week 2

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 2 matches played, 1 of which were correctly predicted, a success rate of 50%.
Here are the predictions for last week’s games.

Predictions for Week 2

Here are the predictions for Week 2. 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.

Q: Did you see that ibuprofen prevents dementia?

A: No

Q: Common 3p anti-inflammatory pill ‘can help prevent dementia’ says new study.  And Prolonged Use Of Anti-Inflammatory Pills May Help Prevent Dementia: Study. And…

A: No

Q: Those quotes in the first headline imply someone really said it

A: Well, that used to be the convention, but apparently not in this case.

Q: Mice?

A: No, not mice. People

Q: Correlations, or randomised trials?

A: Correlations

Q: Is there a paper?

A:  There is a paper.

Q: Has anyone looked at this correlation before?

A: Oh my yes. So many people. There are even randomised trials. The Cochrane Review says “no evidence that it works, and it may be dangerous”

Q: What do the scientists say about that?

A: The trials were too short to show the effect, or they started too late in the disease process.

Q: Is that possible?

A: Sure, it’s possible. Lots of things are possible.

Q: So you don’t believe the paper?

A: It’s a perfectly reasonable paper for consenting scientists in private (I know some of the authors), but it doesn’t justify the recommendation of long-term treatment with these drugs for the prevention of dementia, especially given the potential adverse effects

Q: Well, that’s your opinion. What do the scientists who wrote the paper say?

A: Our results.. do not justify the recommendation of long-term treatment with NSAIDs for the prevention of dementia, given its potential adverse effects. 

“Bowel cancer does not discriminate on race. Māori and Pacific peoples have a similar risk of developing bowel cancer compared to other population groups at a given age.

“It was true that a higher proportion of bowel cancers occur in Māori and Pacific peoples at a younger age, but that is because the overall demographics of those groups are younger. It has always been age that determines bowel cancer risk, not race”

I thought that this required more explanation. Proportion at an age does not seem to me to depend on the demographics of those ages

It’s a good question.  The minister is plausibly correct that the younger age at diagnosis for Māori and Pacific Peoples is driven substantially by demographics.   That is, one reason that few very elderly Māori get diagnosed with bowel cancer is that there aren’t many very elderly Māori.  Fewer Māori make it to be very elderly, and also the Māori population is increasing both because of higher birth rate and because more people are now identifying as Māori to the healthcare system.   If you have the same age-specific incidence rates in two groups, but one group averages younger, the incidence in the younger group will tend to be at younger ages.

That’s not the whole story, or even most of it, for this decision.  The age distribution being quoted is age at diagnosis (because that’s what you have for cancer), but diagnosis isn’t equally distributed. According to the HQSC atlas of health care variation, Māori are more likely to be diagnosed with bowel cancer following emergency presentation, and more likely to die within two years of diagnosis. This means there’s a good case that Māori are more underdiagnosed than New Zealand Europeans.   On the other hand, a lot of the problem with underdiagnosis is not being tested. If people end up just doing one test when they become eligible, and then not bothering later, the optimal age for a single test is more like 60 than 50.   And, as a general principle,  if you want to spend public money to improve health, you typically will do better by spending it on people who are less healthy and have worse access to health care.

In any case, while the headline Bowel cancer screening eligibility age to be lowered for everyone is technically true (since the lower-age screening pilot has already been stopped), it seems to miss the point a little.

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 95 matches played, 69 of which were correctly predicted, a success rate of 72.6%.
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, 95 of which were correctly predicted, a success rate of 75.4%.
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, 12 of which were correctly predicted, a success rate of 80%.
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.

Team Ratings for Week 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 Week 1

Here are the predictions for Week 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.

NZ$ Herald has a piece today about increases in methamphetamine consumption (as measured by wastewater)

The story is about cheap meth imports increasing the supply, with a speculative aside into a decrease in consumption in Ōpōtiki and whether it might be attributable to major gang arrests.

The sudden spike in 2024 is surprising. Normally I would guess that sudden level changes in a time series were due to different definitions of the variable, but it appears to be defined the same way.

It’s obviously tempting to attribute the sudden change to the relaxation of rules on pseudoephedrine sale in 2024, and some people on social media seemed happy to do so.  There are problems, though.

First, the suddenness is still strange. You’d expect the gangs to take a while to ramp up production and sale after years out of the business — and if they were ready on day one, the spike would have been in June rather than July.

Second, that’s a big spike.  There’s about gram and a half of pseudoephedrine in a pack of decongestant tablets, which will make under a gram of meth, so a 20kg jump in meth production is a lot of Sudafed: tens of  thousands of packets per week of a drug sold only by pharmacist prescription. Someone should have noticed.

The Drug Foundation says it’s due to international supply, which seems plausible — we’re seeing  300-500kg seized most quarters recently, which is 15-40kg/week, so unless we’re catching the majority there will be enough getting through to explain wastewater levels.

The Herald also quotes price data from the Drug Trends Survey, which says prices are down. That’s a bit less supportive than it looks. First, prices were only down in roughly a straight line over several years. Second, the say they think demand has saturated, which doesn’t fit the spike. And finally, the last edition of the survey sampled from February to July 2024, so mostly missed the spike

• Petrol price margins are up: RNZ.  These, as we’ve discussed, are based on the difference between the import price and retail price, and include transport and vendor costs (like running petrol stations) as well as profits.  The change from week to week in the margin is still a good indicator that either the efficiency of the system has gone down or the profits have gone up.
• The Trump administration has cited a statistic that only 6% of federal government workers are full-time in their offices. This is facially implausible when you consider how many federal jobs can’t possibly be done remotely. Pro Publica looked into the number, which came from a self-selected online survey of 6338 people claiming to be federal employees, run by a a small news organisation called Federal News Network in the suburbs of Washington.  Say no to statistics from bogus polls!
• The UK is running a big (700,000 women) trial of “AI” to assist in reading mammograms. This isn’t ChatGPT, it’s from earlier generations of image-analysis software that actually works.  The hope is that using software plus one radiologist is at least as good as the current standard of two radiologists, allowing more screening to be done without needing more scarce radiologists. The media coverage is nearly all positive and based on the government’s publicity release, eg, this from the BBC. There’s not a lot of information available about how they will measure success or exactly which “AI” platforms they will use. I couldn’t find a trial registration, though I did find one for a much smaller trial 15-20 years ago on the same question.  One negative piece of media coverage from the New Statesman, for balance.
• A US trial of an oral Covid vaccine, hoping to provide both better protection and easier delivery, has been stopped by the US government just before it was due to start. At the moment this is being described as a ‘pause’ rather than permanent stoppage.

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 87 matches played, 64 of which were correctly predicted, a success rate of 73.6%.
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.