Posts from November 2020 (25)

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 Round 7

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 32 matches played, 23 of which were correctly predicted, a success rate of 71.9%.
Here are the predictions for last week’s games.

Predictions for Round 7

Here are the predictions for Round 7. 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 the Mitre 10 Cup Semi-Finals

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 70 matches played, 46 of which were correctly predicted, a success rate of 65.7%.
Here are the predictions for last week’s games.

Predictions for the Mitre 10 Cup Semi-Finals

Here are the predictions for the Mitre 10 Cup Semi-Finals. 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 have data on a second Covid vaccine candidate, and it’s similar to the first one.  Moderna  released their first analysis results today: out of 95 cases of Covid, 90 were in the placebo group and 5 in the vaccine group . Even better, they had enough cases of serious disease to analyse, and these split 11:0.

Both of the vaccines use the same new technology, where little bits of messenger RNA, coding for the virus spike protein are introduced into your cells. Your cells make the protein just as if they’d been infected and your immune system reacts.  At least, that was the theory, and it does seem to have worked.   We haven’t heard from any of the trials using more traditional technologies, which would produce vaccines that are easier to distribute and may be easier to manufacture by the truckload.

The next important step, fairly soon, is an FDA external advisory committee meeting.  This should be more informative than peer-reviewed publication: it’s peer review, but involving a lot more information than goes into a published paper, and a wider range of reviewers — and it’s done in public.

There are still problems to be considered:

1. The vaccines have not been tested in children or pregnant women. That’s standard, except for treatments specifically aimed at children or pregnant women, but it’s an important gap.  The pregnancy exclusion is probably less important from a public health point of view, since a very small fraction of the population is pregnant at any given time. Kids, though.
2. We don’t know yet how long protection lasts — if it’s only a few months, that’s a problem
3. We don’t know yet how much asymptomatic infection is prevented
4. NZ doesn’t seem to have bought any of the Moderna vaccine yet — the Minister says we’re in negotiations

Also, these vaccines are going to have more short-term side effects than we may be used to: a lot of people will feel a bit average the day after a dose, and a decent chunk will feel pretty average. That’s going to help the vaccine misinformation pushers, especially if health authorities aren’t honest about it.

Simon Collins (and Chris Knox) at the NZ$ Herald have an interesting piece about the relative incomes of university graduates and other people. It’s definitely worth reading (even though you can’t look up Statistics or Data Science or Journalism).  However, there’s a built-in assumption of causation that is not entirely justified

Getting a degree can earn you a cool $1.3 million more over your lifetime than leaving school and going straight into work – but the gains vary wildly depending on what subject you study.

One of the irritating features of Graduation at the University of Auckland is that the Chancellor’s speech always includes a similar claim

We know that, compared to those whose formal education ends in high school, graduates have lower unemployment rates, higher salaries, better career prospects, and better health outcomes.

I actually used this as the topic for an exam question on causal inference in first semester.  The preamble to the question says

Team Ratings for Round 9

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 47 matches played, 34 of which were correctly predicted, a success rate of 72.3%.
Here are the predictions for last week’s games.

Predictions for Round 9

Here are the predictions for Round 9. 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 27 matches played, 19 of which were correctly predicted, a success rate of 70.4%.
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.

So, there’s good news about the Pfizer vaccine.  Some context:

1. What we have now is just a press release. However, the analysis and criteria were specified in advance, and we actually have that document, so it’s less fuzzy than it might be
2. Data are still coming in, so the estimate of vaccine efficacy will change over time to some extent.  In particular, we wouldn’t have heard anything if the estimated efficacy wasn’t at least 63%, so the current estimate is likely a bit too high.  The current estimate is so far above the threshold of 63% that this bias shouldn’t be huge
3. The trial focuses on preventing symptomatic infection. We haven’t heard anything about the impact on serious disease or on asymptomatic disease. The impact on serious disease is, oddly, less important, since the vaccine is good enough for herd immunity. However, if the vaccine (a bit implausibly) had no effect on serious disease and just made symptomatic infections asymptomatic, it wouldn’t be that much use.  Pfizer are collecting this information; it just wasn’t in the press release.
4. The next important step isn’t peer-reviewed publication, it’s the FDA external advisory committee meeting. These are public and involve scientists and doctors external to the FDA who get to ask Pfizer questions and have them answered.  If the advisory committee is strongly in favour of emergency authorisation, I would expect Medsafe to reach the same conclusion.
5. Duration of effect matters.  We cannot possibly know for another year whether protection lasts for a year (which would be plenty).  Very short duration of protection would still have some use for making travel safer and for ring-fencing small outbreaks, but it wouldn’t have much impact on the pandemic
6.  New Zealand is in line for enough vaccine for  750,000 people, and Megan Woods says it could arrive early next year.  That’s not enough to have any noticeable impact on population spread, but it is enough to reduce transmission to border staff and healthcare workers. It might even allow some increase in the safe admission to NZ of temporary workers or students — the government needs to decide how to allocate the vaccine.  Expanding on this: a vaccine could be used to reduce the probability of an outbreak, to increase travel and help the economy, or to reduce the harm of an outbreak (eg vaccinating elderly people). These are all worthwhile and the detailed choice is a policy question.
7. Mass vaccination won’t happen for a while.  Even if other candidate vaccines are effective (increasing the number of suppliers), mass vaccination in NZ is probably at least a year away
8. If the current estimate holds up, the vaccine is effective enough that we might get reasonable herd immunity by vaccinating only people who actually want to be vaccinated, which would make life simpler.
9. The Covid vaccines seem to have a higher rate of mild adverse effects than most vaccines we’re used to. It’s important not to deny these, and it would be useful if there were careful monitoring of adverse event rates in the first wave of NZ vaccine recipients by, eg, the NZ Pharmacovigilance Centre

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 14 matches played, 10 of which were correctly predicted, a success rate of 71.4%.
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 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 63 matches played, 40 of which were correctly predicted, a success rate of 63.5%.
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.