Posts written by Thomas Lumley (2569)

• Jessica Mackenzie on the “dire” wolf story, and how it got that way: “It’s important to consider how sausage like this is made, and I mean the stories—not the actual wolves.”
• Visualisation of the “demise of the love song” from pudding.cool
• Proportions and totals: is the individual risk of Alzheimer’s going down over time? (apparently, yes, even though the total number of cases goes up with the number of older people)
• Australian Associated Press fact check: Claim – 710,000 new voters on the electoral roll include migrants who arrived under Labor.  False: Migrants who arrived under Labor are not eligible to vote in the 2025 election.
• Stuff headline: Traffic ‘worse than Auckland’: Is this New Zealand’s most ‘anti-car’ city? We’re seeing proper use of headline single quotes here — ‘worse than Auckland’ is an attributed quotation in the text. It is, however, attributed to a single motorist.  Headlines about traffic density/slowness really shouldn’t just be one person’s opinion — traffic is measurable, and measured.

The International Statistical Institute is a professional organisation of statisticians. Its membership includes quite a lot of expertise on the production and use of official statistics, and it has a habit of commenting on political interference with official statistics.

The ISI has a statement on US official statistics

The International Statistical Institute (ISI) is concerned about government interference in the compilation and availability of Federal Statistics in the United States of America (USA). A proposed change in measuring and reporting U.S. Gross Domestic Product (GDP) serves as an important and timely example.

The statement goes on to explain that the USA has proposed removing government expenditures from GDP, and that this is both intrinsically a bad idea and also a weakening of international agreements on which official statistics to measure and how to define them.

[Disclaimer: I’m a member of the ISI, but I wasn’t involved in any way in producing this statement]

• Coffee nerd James Hoffman has a good video on an issue that crops up a lot on StatsChat — totals vs means/rates — though in his case it’s about shorter vs longer espresso shots for making flat white/cappucino.
• From Axios: foreigners don’t seem to be visiting the US as much — this is more interesting than it sounds, since a lot of the dip must be short-notice cancellations, which are relatively difficult/expensive.
  
• According to the NZ Herald, Elon Musk wants zero tariffs between the US and Europe. The story doesn’t point out that was very close to the situation a week ago (eg, according to economist Justin Wolfers.)
• Friday’s rain pushed the Auckland dam water levels up nearly four percentage points (conveniently, the total storage is close to 100 GL, so 1 GL is about 1 percentage point), which was bit more than a third of the deficit from average.  While we’re being nitpicky, that should be 9.99% below, not “-9.99% below”
  
• New York has a new subway map
  

Tim Welch has produced a nice Auckland Cycleways Dashboard (it’s a draft at the moment, or ‘beta’ as we nerds say).

Here are some of the University-relevant routes (click to embiggen, as usual)

These are based on the Auckland Transport cycle counters, which are good for the city centre and major bike paths, but less informative for, say, people commuting in from the south, where there aren’t bike lanes or bike counters.

The tariffs announced by President Trump are based on what he describes as tariffs imposed by other countries on the US. These don’t bear any obvious relationship to the numbers that ordinary economists would describe as tariffs

However, a poster on Twitter, @nonagonono, found there is a strong relationship between the claimed tariff and the countries import/export balance with the US

We want to be a little sceptical of relationships that come just from data-dredging, with no real theory, but this relationship is tight enough that it probably isn’t just a coincidence, and probably does tell us something about the definition of ‘tariff’ the President is using.  If so, the ‘tariff’ of 20% that New Zealand allegedly imposes is actually a trade deficit of 20%, which is not quite what I get from NZ trade figures (24%) but is close enough that some slight changes in definition might explain it.

One News had a story based on a press release from NZ Food Network.  NZFN are a very worthwhile organisation. They coordinate donations and purchasing of bulk food for food banks, which they same amounts to about 45% of  the food being distributed.   If you were looking to donate to an organisation that helps feed people in this country, they look like a cost-effective choice. NZFN also run a food bank survey and a food security snapshot to find out about national needs and supply by food banks.

The headline figure in the press release is that the food banks “provided food to over 500,000 individuals each month”, based on the current survey. That’s a lot.

One News, but not the press release, said this was an all-time high.  Looking at previous annual reports and information sheets from NZFN, it doesn’t seem to be.  NZFN reported 454,000 in the first half of 2024, but their 2024 Annual Report said 655,152 for the second half of 2023 and the 2023 annual report says 480,104.  The number has been close to 10% of the New Zealand population ever since NZFN really got going. The scandal isn’t that the number is up, it’s that the number has been high for years!

What has changed noticeably is the total amount of food NZFN has been able to distribute.  The 2022 annual reports says about 8.6 million kg, the 2024 annual report says 5.6 million, and the 2024/2025 summer newsletter says 6.3 million.  They lost some government funding to purchase food, even as demand was increasing.  (If you look at the current press release you see a higher number that that for total food distributed, but I think that’s total distributed by the food hubs, rather than by NZFN)

I said “the number” is close to 10% of the population.  It’s a bit hard to find out exactly what this number means: is it genuinely unique people fed per month? Do the food hubs actually count how many people each recipient is feeding, and track individual visitors?  The reason I’m a bit suspicious about the number is a 2023 press release

Over half a million people are now being supported by NZFN food hubs each month but there is still a growing need. That works out to 1,868,491 more people being supported by NZFN, than they were in January 2020.

It’s not possible to get a total number of extra people from a monthly number, because you’d need to track individual people over the whole year; you can only get total number of visits.  Given this, it looks possible that that the 500,000 per month might also be total number of visits rather than unique monthly visitors.  It would still be a lot, either way.

You might think that I should answer this question by contacting NZFN rather than guessing.  I’m not sure I (as a One News reader) should have to, but I did actually try that.

Nature magazine (yes, that one) has a headline 75% of US scientists who answered Nature poll consider leaving.

This is a more honest phrasing that one usually gets in bogus poll headlines, but it’s still bogus.  The ‘poll’ was

Responses were solicited earlier this month on the journal’s website, on social media and in the Nature Briefing e-mail newsletter. Roughly 1,650 people completed the survey.

The other problem with the poll is that ’emigrational ideation’, as one might call it, is a very low bar. Lots of people consider doing things. Many fewer actually do them. People having been claiming they are considering leaving the US for a long time, and we don’t know from the ‘poll’ how the current numbers compare to the usual state of affairs. Remember this cartoon, from 2006:

In fact, I think it’s quite likely that there are more scientists than before actively looking into leaving the US.  Anecdotally, we are getting more enquiries here and more US applicants to advertised positions.  You might think this sort of anecdata is a pretty weak basis for conclusions . You’d be right, but it’s still better than a bogus poll.

Q: Did you see ebikes are good for your brain? If you’re old.

A: How old?

Q: Over 50

A: That’s not… Ahem. That’s a very inclusive definition of  ‘old’, isn’t it?

Q: Does it work?

A: Who knows? It might.

Q: Does this research show it works?

A: What would we want to check?

Q: Mice or people?

A: Good. People, not mice.

Q: Random allocation of people or just correlations?

A: Yes, that’s right.  This one is … somewhere in between.

Q: What’s in between randomly allocating people and just seeing what they choose? You flip a coin, but with your eyes closed?

A:  Well…

Participants were pseudo-randomly assigned to one of three groups: pedal cycling, e-bike or non-cycling control groups. Priority was given to filling the cycling spots then controls were recruited to match sample characteristics. The control group were recruited after the experimental groups had started to be run so that we could match age and gender in the control group with those participants in the experimental groups. The control group were aware that they would not be cycling during the trial and those in the experimental group were all re-engaging with cycling.

Q: So, comparing people who signed up to do cycling with people who signed up to avoid cycling and other exercise.

A: Yes, but in the context of cycling research, not just random people asked to not do any extra exercise.

Q: And did the cycling group have better brains?

A: They measured a whole lot of things. Eight different multi-question assessments. Some of those improved and some didn’t

Q: Is that what they expected?

A: Not really, no. They expected improvements in a lot of the things that didn’t go up

In line with our predictions, we found trends for improvement in executive function in the Stroop task and letter updating task in both cycling groups compared to baseline and the non-cycling controls. We also found improvement in speed of processing for go trials in the Stop-It signal task only for e-bike participants during the intervention. Measures of memory and spatial functioning did not show an effect of cycling. Furthermore, we found increases in self-reported mental health on the SF-36 health survey for only the e-bike cycling group. Despite strong evidence from previous studies for an increase in well-being after exercise and the impacts of the outdoor environment on this aspect of mental health, we did not find increases on the PWB, SL or PANAS questionnaires.

Q: Could it just be the study was too small to give reliable conclusions?

A: Well, if that’s the explanation, then the study is too small to support press releases and media attention.

Q: So e-bikes are bad?

A: E-bikes are a good form of low-carbon transport, especially in hilly cities with nice climates, and let you get some, but not too much, exercise.   I don’t think they need special effects on the brain to be popular.

Via the US website Electrek, which does news about electric vehicles and adjacent subjects, a story about bogus polls.

A bogus online clicky poll in Germany got 100,000 clicks and found that 94% of the time that a button was clicked, it corresponded to “absolutely not willing to buy a Tesla”.  Electrek calls this “100,000 Germans”, based on very little evidence.

The poll kept running.  By the time it had 470,000 clicks, only 29% of the clicks corresponded to “absolutely not willing to buy a Tesla”.  Quite a lot of these clicks — 253,000 — came from just two IP addresses in the US. A bit of maths shows that the clicks from the two US addresses made up about three-quarters of the pro-Tesla clicks.

The magazine, T-Online, was forced to the shocking conclusion that its meaningless customer-engagement exercise had been manipulated by someone else’s meaningless customer-engagement exercise.

From Pew Research, a bizarre error

A few Reddit users shared screenshots from a variety of surveys, where questions that should have offered answer options of “yes” and “no” instead offered the choices “forks” and “no.”

In summary: web browsers may offer you the option to translate web pages automatically from languages you don’t read to languages you do read.  That is, they have the option to silently rewrite web pages before showing them to you. They aren’t 100% reliable either in guessing which web pages are actually in a foreign language and need translating or in translating those pages to, as it might be, English.