Stats Chat

There’s a 1News headline Only 1 in 4 Aucklanders back Wayne Brown’s sweeping cuts

I was expecting this to be based on proportions supporting the cuts in public submissions, but I was glad to see that the Council commissioned a proper survey in addition to accepting general comments and 1News reported it correctly.  That’s an excellent combination: open public comment allows people to point out problems or solutions you haven’t considered and a survey allows quantitative measurement for issues where you know the options in advance. More organisations should do this.

As you’d expect, trying to get quantitative results from the public comment doesn’t work very well. For example, 1News reported that 40% of submitters didn’t want any cuts, as opposed to the estimate of 7% for all Auckland in the survey.  People who have something to say are more likely to say it.

The number of submissions was very large: more than 10% of the number of votes in the mayoral election.  Even so, the submissions are very unrepresentative. That’s not a problem if you aren’t trying to get quantitative results; having the input biased towards experts and people who care a lot can be helpful.  It would be a problem if you were just counting the results.

Stuff has an important report on road injuries in Auckland, based on a review by Auckland Transport (that doesn’t seem to be available).   They looked at the numbers of serious injuries over three years, both as reported by the police crash analysis system and as reported by the hospitals where the people turned up for treatment. These numbers were not the same

Even the discrepancy for cars is a bit surprising: ‘serious injuries’ here mean hospital admission (an overnight stay).  It’s not clear whether the police are missing half the serious-injury crashes or under-reporting how many people end up in hospital, but I would have expected more completeness of reporting for hospitalisation of people in vehicles. (According to the law, even accidents involving bikes or e-scooters without cars  that result in injury have to be reported to the police, but I’m less surprised this doesn’t happen.)

Some of the bike and pedestrian and ‘transport device’ injuries that are being missed will be crashes that didn’t involve cars.  That’s the dashed/solid distinction in the graph. The data match international research on e-scooter crashes suggesting that most injuries are to the rider, and so may be relatively less likely to get reported to police.  For bikes, a potentially worrying category is injuries involving stationary cars — ‘doorings’ — which might be less likely to get reported than those involving moving cars.

Another important concern, though, is the definition of ‘serious injury’. An injury causing broken bones and resulting in weeks or months of significant disability, but not involving an overnight hospital stay, would not be meet the threshold.  This implies even the MoH statistics are also missing a lot of injuries that a normal person would call ‘serious’.

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 64 matches played, 36 of which were correctly predicted, a success rate of 56.2%.
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 Week 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 144 matches played, 102 of which were correctly predicted, a success rate of 70.8%.
Here are the predictions for last week’s games.

Predictions for Week 19

Here are the predictions for Week 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 Round 24

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 161 matches played, 116 of which were correctly predicted, a success rate of 72%.
Here are the predictions for last week’s games.

Predictions for Round 24

Here are the predictions for Round 24. 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 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 48 matches played, 37 of which were correctly predicted, a success rate of 77.1%.
Here are the predictions for last week’s games.

Predictions for Week 10

Here are the predictions for Week 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 24

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

Predictions for Round 24

Here are the predictions for Round 24. 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 8

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 28 matches played, 18 of which were correctly predicted, a success rate of 64.3%.
Here are the predictions for last week’s games.

Predictions for Round 8

Here are the predictions for Round 8. 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 8

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 56 matches played, 30 of which were correctly predicted, a success rate of 53.6%.
Here are the predictions for last week’s games.

Predictions for Round 8

Here are the predictions for Round 8. 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 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 136 matches played, 98 of which were correctly predicted, a success rate of 72.1%.
Here are the predictions for last week’s games.

Predictions for Week 18

Here are the predictions for Week 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.