Posts from December 2020 (23)

Team Ratings for Round 13

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 77 matches played, 53 of which were correctly predicted, a success rate of 68.8%.
Here are the predictions for last week’s games.

Predictions for Round 13

Here are the predictions for Round 13. 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 5

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 22 matches played, 13 of which were correctly predicted, a success rate of 59.1%.
Here are the predictions for last week’s games.

Predictions for Round 5

Here are the predictions for Round 5. 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 10

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 46 matches played, 32 of which were correctly predicted, a success rate of 69.6%.
Here are the predictions for last week’s games.

Predictions for Round 10

Here are the predictions for Round 10. 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 6

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 13 matches played, 10 of which were correctly predicted, a success rate of 76.9%.
Here are the predictions for last week’s games.

Predictions for Round 6

Here are the predictions for Round 6. 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 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 71 matches played, 48 of which were correctly predicted, a success rate of 67.6%.
Here are the predictions for last week’s games.

Predictions for Round 12

Here are the predictions for Round 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 5

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 11 matches played, 9 of which were correctly predicted, a success rate of 81.8%.
Here are the predictions for last week’s games.

Predictions for Round 5

Here are the predictions for Round 5. 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.

From the usually-reliable XKCD

The graphs of cumulative Covid incidence for the Pfizer and Moderna vaccine trials are very impressive: the vaccines are effective.  We need to relabel the axes to see what’s wrong with the cartoon

If the trials had just been about vaccine effectiveness, they would have been much shorter.  Delaying the actual use of the vaccine, when the US alone is getting 1.5 million cases a week, just in order to get a pretty graph and avoid using statistics would be … ethically questionable. No matter how you felt about your high school stats class. If we only cared about effectiveness, the graph would look more like

The reason the trials ran so long was to assess safety.  Everyone in the trials was followed up for six weeks after their second vaccine dose, because that’s long enough to see any adverse reactions that have been seen for past vaccines.  The very high rate of new cases in the US and other countries involved in the trials, together with the high effectiveness, meant that effectiveness could be demonstrated much more quickly than safety — but safety is important.

Safety is especially important for us in NZ, where there is less urgency than in the US or UK.  Medsafe will be looking at whether to approve the vaccines and under what conditions, and they’ll be doing more than “We reject the null hypothesis based on the ‘hot damn, check out this chart’ test.”

Team Ratings for Round 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 9 matches played, 8 of which were correctly predicted, a success rate of 88.9%.
Here are the predictions for last week’s games.

Predictions for Round 4

Here are the predictions for Round 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.

We now have fairly detailed data on the second Covid vaccine, the one from Moderna.

• Ahead of the FDA advisory committee meeting this Friday morning, briefings from the FDA staff and from Moderna
• Summary Twitter thread from Hilda Bastian
• From Ars Technica
• From Washington Post

Again, I’ll add more as I see them.

From the Herald

A coroner has warned of the dangers of driving while impaired by drugs after reviewing nine fatal vehicle crashes and finding cannabis use was implicated in six of them.

but further down in the story

He was found to be almost five times the legal drink-drive limit while also testing positive for cannabis and its constituent element tetrahydrocannabinol (THC).

At a blood alcohol concentration of 0.25%, your risk of a crash has increased by more than a factor of 100.  That is, more than 99 out of 100 crashes in people with blood alcohol of 0.25% will be caused by the alcohol. You don’t need cannabis use to explain a crash like this, and it’s not clear that there was any relevant cannabis use.  The report says the driver was at a BBQ where people were drinking. There is no suggestion in the story that anyone was smoking weed (though it isn’t specifically ruled out).

The description of testing positive for “cannabis and its constituent element tetrahydrocannabinol” is also a bit weird.  I think they just tested for THC; that’s what I’ve seen in previous reports from ESR, who do the testing.  And they can pick up very small amounts of THC; a 2012 publication on tests after fatal crashes reported a range from approximately 0.1 ng/mL to 44 ng/mL (mean 5.6 ng/mL) concentration in blood samples.  Some of these people will have been impaired by THC, but by no means all of them.  ESR are careful about how they report this sort of thing, and don’t write things like “cannabis use was implicated” when they mean “THC was detectable”, but the coroner seems to be less careful.

The coroner didn’t say anything about alcohol use in the other eight fatal vehicle crashes.  You’d hope, if he’s making those sorts of statements about drugs that some of the crashes didn’t involve large amounts of alcohol and had evidence of recent consumption of cannabis or some other reason to think it was really implicated, but you’d also hope he’d make that clear if it was true.