Posts filed under General (3148)

There’s an interesting poll in the NZ$ Herald asking whether the four-day extension to the Auckland level 3 ‘lockdown-lite’ was appropriate or not. Here’s a graph of the regional results (excluding the worryingly-small fration of “don’t knows”). The purples are ‘yes, should have been extended’, with the light purple being ‘the four day extension was appropriate’ and the dark being ‘longer would have been better’. The oranges are ‘no, should not’, with the light orange being ‘should not have been extended’ and the dark being ‘should not have happened at all’

As you can see, there’s pretty strong consensus across the country.  You’d expect people outside Auckland, who get the benefits but with less of the cost, to want tighter restrictions, and the patterns seem to fit that.

The Herald also explores differences by age, gender, and income. It’s hard to say anything too strong about many of the differences, because we’re only quoted a margin of error for the whole survey, not for any of the subgroups.  In some cases I can work it out: if Auckland and Canterbury were represented in the sample in proportion to their actual population sizes, the difference between the purple bars would be right about at the margin of error.  In general, though, the overall margin of error is pretty useless for most of what makes the story interesting.

Oh, and also.

Auckland is strongly divided over whether extending the lockdown was an appropriate response to the resurgence of Covid-19, a new poll shows.

But the exclusive new poll shows rest of the country was far more accepting of the Super City being kept in alert level 3 for almost three weeks – with many wanting it extended even longer.

Emphasis added.

No. That’s really not what the poll says

Team Ratings for Round 10

As an indication of the care needed at present in determining home ground advantage, the comprehensive scores site flashscore.com.au still has the Rebels v Waratahs game as being played in Melbourne. (Click on the match result to see the scorers and times and match details at the bottom.) Fortunately I checked beforehand that it was to be played in Sydney so I gave the Waratahs home ground advantage and predicted them to win. Otherwise I would have predicted the Rebels, even if played on a neutral ground.

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 18 matches played, 15 of which were correctly predicted, a success rate of 83.3%.
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 18

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 102 matches played, 66 of which were correctly predicted, a success rate of 64.7%.
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 the 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 101 matches played, 78 of which were correctly predicted, a success rate of 77.2%.
Here are the predictions for last week’s games.

Predictions for the Semi-finals

Here are the predictions for the 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.

Team Ratings for Round 17

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 128 matches played, 88 of which were correctly predicted, a success rate of 68.8%.
Here are the predictions for last week’s games.

Predictions for Round 17

Here are the predictions for Round 17. 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 17

I got caught out a bit this round with games being played earlier in the week and then again on the weekend. As usual my predictions are what they would have been before the games were played, the predictions are produced by running my algorithm over the past data and information about home grounds.

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 96 matches played, 61 of which were correctly predicted, a success rate of 63.5%.
Here are the predictions for last week’s games.

Predictions for Round 17

Here are the predictions for Round 17. 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.

Auckland is going back to level 2 (God willing and the creek don’t rise) on Monday.  Together with my local circle of health and stats nerds, I’m viewing this with some concern. It hasn’t been very long since we had a case show up with no previously known contact to the cluster. Like, Tuesday.  It’s quite possible there are still a few other people in the cluster who haven’t been found yet.

The concern is not that it will actually be dangerous on Monday to be going to work or going shopping. The number of undetected cases will be small; your chance of getting infected on Monday is tiny.  The problem is, as long as there are undetected, infectious cases, your chance of getting infected on Tuesday is very slightly higher. And slightly higher again on Wednesday, and so on in exponential increase. Eventually, it may get dangerous, and  stopping it then is much more costly in health and freedom and money.  In Victoria today they are talking  about the psychological boost of getting a day with less than 100 new cases. If we’re careful and lucky, the current testing and tracing will be enough to stop this cluster exploding; if we’re not, maybe not.

One challenge in COVID risk communication is that the risk is longer-term and social, not immediate and individual. It’s important that as many  people as possible take precautions against spreading the virus: distancing, masks, getting tested if you have symptoms, working from home if that’s feasible, avoiding places with poor ventilation. But it’s not so much important for your or your family’s immediate safety: the risk is currently very low. If someone jogs past you at close range without a mask or stands a bit too close in  a supermarket line, you don’t need to panic — you almost certainly won’t catch the coronavirus. On the other hand, the more people behave that way, the more chance that they outbreak will slowly get out of control.  The appropriate level of care is a lot higher than the appropriate level of fear.

Ideally, everyone would be as careful as if the virus was everywhere, but nowhere near as scared as if it was everywhere. That’s a very difficult balance, and a reason for the ‘be kind’  message when it doesn’t quite work out.

Q: Did you see this study saying vaping makes you five times more likely to get COVID?

A: Yes, but it’s not in the news, so it doesn’t count for StatsChat

Q: Newshub covered it.

A: Ok. Not entirely convinced

Q: They did a survey and they did lots of reweighting, the way you like. And said exactly what questions they asked.

A: Yes…

Q: So it’s not dodgy like the paper about heartburn drugs

A:  No, not like that.

Q: What’s your problem, then

A: The first problem is the proportion of people with COVID tests. No, actually the first problem is that COVID is so rare that this isn’t a reliable way to estimate proportions, and the second problem is that getting a test depended on a lot of other factors back then.  The third problem is the proportion of people with COVID tests

Q: Which is?

A:  Over 5% of people 13-17 and over 10% of people 21-24. By May 14, when the total cumulative number of tests in the whole US was only about 5% of the population — and you’d expect lower testing rates in younger people.

Q: Where are those numbers in the paper?

A: It’s a combination of the user and non-user columns in Table 1, using the proportions in the Supplementary Material. Which, again, the authors should get credit for providing.  What they call “COVID-related symptoms” are also very high: 14% of non-vapers and 26% of vapers reported having the symptoms right at the time they were surveyed.

Q: You’d think we would know if vaping increased these symptoms that much, separately from COVID. But if they oversampled people at high risk of COVID, it should at least be comparable across their survey

A: They did separate surveys for users and non-users of e-cigarettes, so that’s not actually obvious.

Q: But weighting?

A: Yes, but that doesn’t help as much with matching the surveys to each other, especially as they don’t have separate census totals for vapers and non-vapers.  In particular, in mid-May COVID was concentrated in relatively small areas of the US, and it would have been more valuable to make sure the locations matched up.

Q: But we know that smokers are at higher risk of catching the coronavirus, so this just confirms that.

A: Surprisingly, no.  Smokers don’t seem to be at higher risk of getting infection — and I guarantee that it’s not because no-one tried to show they were.  They may be at higher risk of getting seriously sick if they are infected, but even that’s not as clear as you’d expect.

Q: So should we believe this?

A: It’s not as simple as that.  This study does provide some evidence, but not as strong evidence as the researchers think. It certainly isn’t strong enough evidence to change policy on the regulation of e-cigarettes; whatever  you believed about that before seeing this study, you should believe about the same afterwards. And you probably do — it’s not a topic where people are noted for changing their minds.

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 16 matches played, 13 of which were correctly predicted, a success rate of 81.2%.
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 16

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 90 matches played, 58 of which were correctly predicted, a success rate of 64.4%.
Here are the predictions for last week’s games.

Predictions for Round 16

Here are the predictions for Round 16. 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.