Posts from February 2014 (45)

The UK is trying to set up a national research database of medical records from the National Health Service. That’s a good idea. New Zealand has one, and many of the larger fragments of the US medical system have their own.  As well as helping improve the performance of the National Health Service, the UK database could be used for research that would help people around the world; for example, detecting adverse effects of drugs.

A UK drug safety system would be more informative than the NZ one, because it involves so many more people. It might even be more informative than the US systems because the NHS it is comprehensive, not selective. That’s only true if everyone’s data is in the system, and that will only be possible if most people trust the system to protect their privacy.  Since it’s not really possible for the average person to tell if the system is trustworthy, it needs to be designed and implemented well enough that there aren’t any reasonable people with serious criticisms for inevitable opponents of the scheme to point to.

Sadly, the promoters of the database have at best been a bit careless about some of their claims, as Ben Goldacre describes. Some descriptions of the system have implied that making the data anonymous — removing obvious identifiers — is a strong safeguard. It isn’t: re-identification is often possible. It isn’t clear whether this was an omission in describing the safeguards or in designing them, but it’s unfortunate either way.

Worse still, the Telegraph has a story claiming that 13 years of complete British hospital records were sold to insurers, who used them to improve risk estimates and increase premiums. This is a problem because one of the key guarantees of the system was going to be that data wouldn’t get to insurers. The data release was under the old rules, not from the new proposed database, but it still is Not Helpful if you’re trying to persuade people not to worry.

There’s an interesting story in the Herald with interactive graphics comparing internal and external NCEA assessments for different subjects, levels, and decile of schools, over time.  The main thing I might change about the graphic is to display over deciles rather than over years, since that’s where the action is.

The general picture is fairly consistent: in low-decile schools, the students get substantially better grades on internal assessment than external. The difference is progressively smaller as you move up the decile scale, in some cases vanishing.  Interpreting the results is more difficult.

The lead says that students do better away from the pressure of exams, which is one explanation. Another, given by Professor Carnegie from VUW, is that the internal assessment is not very reliable. There are many alternatives views given in the story, and even some who says the differences over decile are reasonable and appropriate.

From Stuff

But Tertiary Education Minister Steven Joyce has made it clear they are not going to get any more in this year’s Budget, and says students already have “one of the most generous support systems in the world”.

This is sufficiently vague that you can probably find a sense in which it’s true, and so could Mr Joyce’s counterparts in most other countries. For example, the Hong Kong system provides slightly larger loans and similar tuition subsidy, but charges (low) interest on the loans from day 1.  The US system allows much larger student loans and significant means-tested non-loan support, but provides much less public subsidy for tuition.  The UK system is more generous for students in low-income households but less generous for students in high-income households. It must be hard to find criteria where the NZ system is more generous than Germany or some other Western European countries, though.

What’s a bit more surprising is that the story treats inflation as basically a matter of opinion

From January 1999 to December 2008, they could borrow up to $150 a week. The limit has risen slowly since, and now stands at $173.56, which Mr Joyce says is in line with the rise in inflation.

vs

But Victoria University third-year student Annabelle Nichols said she and many of her friends were left in the red at the end of each week, and disagreed with Mr Joyce that living costs had kept pace with inflation.

If you look at the RBNZ online inflation calculator, you find that $150 in the first quarter of 1999 translates to $212.06 in the first quarter of 2014 using overall CPI, $217.38 using the food category, $346.62 using the housing category, $221.11 in the transport category, and $155.72 in the clothing category. Unless students are expected to spend the majority of their money on clothing, this seems inconsistent with Mr Joyce’s claim.

It’s possible that the Treasury has done specific living-cost modelling for students and that they do face lower effective inflation rates than the rest of the population, but given the location of many universities in places with expensive housing, that’s a bit surprising and would have been worth mentioning explicitly.

[Update: Mr Joyce was talking about just the period since 2008 ,when the loan limit stopped declining in real terms. That doesn’t affect my main point, which is that reporters shouldn’t treat inflation adjustment as a matter of opinion — they should check. Also, while 2008 is a relevant starting point for Mr Joyce, it’s not clear that it is for anyone else]

Congratulations to statschat.org.nz’s Thomas Lumley, Professor of Biostatistics in the Department of Statistics at the University of Auckland, who as of today is a new columnist for the venerable New Zealand Listener (in the edition dated March 1-7; its cover story is the third anniversary of the fatal Christchurch earthquake). Stats Chat staffers are delighted that we now have another way to target stats crimes and shed some light on statistics in the media every day.

The introductory blurb on the Listener’s Letters is below (complete with evidence that Julie can’t make a straight scan):

And Thomas’ his first column asks this question: How much of the difference between women’s and men’s wages is a result of individual choice? Have a read of Closing the gap.

US GDP, measured by locations of businesses, from Reddit user atrubetskoy

Now, GDP isn’t really well-defined at that sort of spatial scale — employees and businesses and customers need not all live in the same small census area — and the data are old, but it still looks striking.

However, in this map, the orange areas have 50% of the US population

and since I used whole cities/counties as units, the orange areas could be made a lot smaller with a bit of effort, giving a better approximation to the GDP map.

From XKCD 

As he comments this StatsChat post, Jim Lindgren did a similar test of the astrology/astronomy confusion hypothesis, with different results.

I replicated Landers study using the two NSF questions actually used, rather than questions that Landers made up. I then asked two followup questions designed to probe what the respondents meant by astrology.

If you ask the actual questions used in the NSF study and probe further than Landers did, you get completely different results from Landers’. In my sample, only 1 of 108 respondents seemed confused in the way that Landers hypothesized.

You can read about my replication in my blog post at the Washington Post:

http://www.washingtonpost.com/news/volokh-conspiracy/wp/2014/02/18/did-people-confuse-astronomy-with-astrology-in-the-nsf-study/

Team Ratings for Round 2

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

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 2 matches played, 1 of which was correctly predicted, a success rate of 50%.

Here are the predictions for last week’s games.

Predictions for Round 2

Here are the predictions for Round 2. 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.

Prompted by Siouxsie Wiles’s report of talking to an anti-vivisectionist demonstrator, here are two charts from the annual report of the National Animal Ethics Advisory Committee. These are the people who monitor the use of animals in research, testing, and teaching in New Zealand.

The first chart shows what types of animals are used and what happens to them afterwards

More than half are sheep and cattle, mostly cattle, and mostly subjected to things like breeding or eating different types of feed.  There are quite a lot of mice used in biological research, though the numbers are decreasing (down 24% last year) partly because they are being replaced by zebrafish. None are monkeys.

About half of the research is commercial, with about a quarter at universities

Some people will still be opposed to livestock research because they’re opposed to livestock farming. Some people still  disapprove of the use of mice in biomedical research. But anyone who wants to campaign on those issues should be clear that those are the issues.

• How one student mildly incovenienced the NRA using open data. (via @hmason)

• From Stuff: Having a nasty bout of shingles is becoming more common in New Zealand [no data or anecdote given to support this], with the numbers of those at high-risk of infection on the rise. [when that’s defined just as older people]

• An interactive demonstration of conditional probability. I don’t know if it’s useful, because I already understand conditional probability, but it’s pretty.

From Tracker, the blog of the MIT journalism school, in a long post on the habit of reprinting lightly-edited press releases and calling it science journalism

Let’s be clear: The aim of Stanford press releases is to promote Stanford; not to enrich the readers of The Washington Post. The same is true of the University of Zurich’s releases. And of all the other releases that have been reprinted in the Post.

And the aim of the Post is–or should be–something quite different. And the paper says so in a lengthy credo on its website. “Through lively, sometimes humorous, but always rigorously researched stories, we try to separate the truths from the half-truths to help people make smarter HEALTH & SCIENCE care choices for themselves and their families.” It goes on: “We insist on getting information from the most reliable sources—the respected authorities in a particular field and the most solid studies in peer-reviewed medical journals. We’re fiercely independent of any commercial interest or advocacy group.” And that would include doctors and universities?