Posts filed under General (3144)

Team Ratings for Round 14

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 91 matches played, 65 of which were correctly predicted, a success rate of 71.4%.
Here are the predictions for last week’s games.

Predictions for Round 14

Here are the predictions for Round 14. 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.

Stuff has a new fact-check column, “The Whole Truth”, and there’s a good example with discussion of youth crime trends, by James Halpin.

The graphs are just the sort of thing I use and recommend: enough history and (where appropriate) enough context to see what trends are just continuing and where things might have changed

It’s clear that the orange line in the left panel is different from basically everything else.  It looks as though the blue line might be going up, but it’s clearly still lower than it was in recent years.

That is, one category of crime in one age group is up.  Overall, robberies and burglaries, even those specifically committed by young people, aren’t increasing, but these vehicle crimes are.  They go on to say that ram-raids by young people are up; the absolute numbers are small, but these are serious crimes, with damage out of proportion to the amount stolen. It’s unlikely to be reporting bias — again, these are serious crimes that would usually be reported.

The data can’t really support a general ‘kids today’ narrative, but there is a real, specific, problem.

• I’ve often complained about misleading bar graphs in reporting electoral opinion polls. 1News just punted on the whole issue with this:
  
• The cost of the Meola Road rebuild, $47.5 million, has been inaccurately portrayed as the cost of the bike lane that’s a minor component of it. Twitter user @ArcCyclist got the actual breakdown from the Council:
  
  While I’m at it, I do want to note one way it’s a bad table: the cycleway number is given to whole dollars, with everything else given in cents, so it looks even smaller than it really is. You usually don’t want to delete trailing zeroes in a table.
• The ESR Covid wastewater dashboard is now at poops.nz. Yes, really.
• There’s a new “technical report for future UK Chief Medical Officers, Government Chief Scientific Advisers, National Medical Directors and public health leaders in a pandemic” from the UK. Even if you aren’t among that exalted company, some of the information may be useful to public citizens as well
• The Ministry of Health is seeking public comment on something it wrote about ‘precision health’. There might be StatsChat readers who have reckons.
• Eric Crampton notes that cost-benefit ratios for transport projects are defined in an idiosyncratic way that makes them hard to compare either with each other or with non-transport projects.
• The first drug to convincingly delay Type I diabetes onset has been approved. The average benefit is about two years, and the treatment will be marketed at US$200,000.  Cost-effectiveness research suggests this is way more than it’s worth for most people, even in the US where insulin for Type I diabetes is very expensive.

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 69 matches played, 53 of which were correctly predicted, a success rate of 76.8%.
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 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 84 matches played, 62 of which were correctly predicted, a success rate of 73.8%.
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 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 57 matches played, 37 of which were correctly predicted, a success rate of 64.9%.
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 Week 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 61 matches played, 46 of which were correctly predicted, a success rate of 75.4%.
Here are the predictions for last week’s games.

Predictions for Week 9

Here are the predictions for Week 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 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 77 matches played, 56 of which were correctly predicted, a success rate of 72.7%.
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 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 53 matches played, 34 of which were correctly predicted, a success rate of 64.2%.
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.

From the Guardian: Computer says there is a 80.58% probability painting is a real Renoir. The story goes on to say Dr Carina Popovici, Art Recognition’s CEO, believes that this ability to put a number on the degree of uncertainty is important.

It’s definitely valuable to put a number on the degree of uncertainty. What’s much less clear is that it’s valuable to put a number on the uncertainty to four-digit precision.   Let’s think about what it would take to be that precise.

If the 80.58% number was estimated from a proportion of observed data in some sense, quoting it to four digits would only make sense if the uncertainty was less than about 0.05%.  A standard error of 0.05% would need a sample size of more than five hundred million.

Another way you can get an estimate with high precision is including subjective expert opinion, which would be entirely appropriate in a context like this. There’s no limit to how precise this can be for the person whose opinion it is — you believe exactly what you believe — but there are very strong limits on how precise it can realistically be as a guide to others.  If the computer isn’t the one buying the Renoir, other people probably shouldn’t care about its opinion to more than one or two digits accuracy.

Sometimes when you come up with an estimate you want to quote it to higher precision than is directly useful — lots of statistical software, including some I write, quotes four or more digits in the default output. This allows rounding to happen closer to the point of use, such as before it’s in a headline in the mainstream media.