Posts filed under General (3152)

• The Australian has a story about religion in Australia, with the figure of “a touch under 70 per cent nominating a religious affiliation.” That’s only true if you include the 10.6% “Religious affiliation not stated” as nominating a religious affiliation.  The true figure is 56.8%.  You could stretch that to 63.5% of those who answered, but that’s assuming (at least implicitly) that the no-answers are just as likely to be religious as those who stated an affiliation. (via John Quiggin)

• This is why 10 stunning photos will make you cry tears of joy.

• From the Dallas Morning News:Steve Doud, a subscriber from Plano, emailed me to say he’d read something in the June 21 Dallas Morning News that couldn’t possibly be true.An eight-paragraph Washington Post article on page 10A reported on a national study about kids and guns. The last sentence said 4.2 percent of American kids have witnessed a shooting in the past year.

• There’s news in the UK claiming that Ryanair’s “random” seat allocation for people who don’t pay extra to pick a set isn’t random and favours middle seats, including something from Oxford University statisticians. It’s clear that the seats are not a simple random sample of all seats on the plane, but that isn’t what Ryanair is claiming. The airline’s defence, that the people who pay to pick seats usually pick the better ones, seems pretty plausible to me.

• Buzzfeed says the US is going to spend $7.1 billion on food for the Fourth of July weekend. If you think about this as 321 million people for a weekend plus a holiday, it’s not as impressive.  Maybe they’re only counting some types of food?  This violates two of the three basic rules for big dollar numbers: they need to be per-capita, inflation-adjusted, and compared to something. (via Fred Clark)

• “A sloppy attitude towards statistics has led to exaggerated and unjustified claims becoming commonplace in science, according to one of Britain’s most eminent statisticians.” David Spiegelhalter, reported in the Guardian

And finally, a picture of one of the causes of overdiagnosis in cancer — and one of the causes of illusory improvements in survival from earlier screening.

What is overdiagnosis? This refers to the detection of cancers that would never cause harm: https://t.co/tEJ7I54a1z pic.twitter.com/VY8okHOL9q

— National Cancer Inst (@theNCI) June 30, 2017

StatsChat has been going long enough that I can look back at stories I disparaged in the past and see how well they held up.

To begin with, an April 2012 story about a vaccine for heart disease that might be available within five years. It wasn’t.

There doesn’t seem to have been any real development of this vaccine. But there is a 2017  research paper that has a new promising approach to vaccinating against heart disease.

You might have seen a story in the Guardian (don’t click while you’re eating), headlined “Popularity of sushi has brought rise in parasitic infections, warn doctors“.

There’s a link (also not safe for dinner) to a single case report of anisakiasis in Portugal attributed to sushi. The case report says

Most of the cases were described in Japan due to food habits; however, it has been increasingly recognised in Western countries.2 ,3

If you follow those references, you find a report of 2 cases in Italy, due to marinated raw anchovies, and 25 cases in Spain, due to marinated raw anchovies.

Anisakiasis is now being diagnosed in western countries, but if we can believe the evidence behind this story the cases are mostly from traditional European food practices, not because of  sushi.

Q: Did you see cannabis is actually better for pain relief than opioids?

A: Not convinced.

Q: But 92%97% of patients said they preferred it! Even if they’d tried opioids! You’re not saying you know better than them, are you?

A: Imagine you had a survey of people who cycle to work, including lots of people who own cars.

Q: Ok.

A: What proportion of those people would say they’d choose to cycle to work instead of driving?

Q: I don’t know, I don’t drive.

A:  Imagine you had a survey of people who cycle to work, including lots of people who have perfectly good bus routes as alternatives.

Q: Ok.

A: What proportion of those people would say they’d choose to cycle to work instead of driving or taking the bus?

Q: A lot.

A: Maybe even 92%97%?

Q: Maybe.

A: The survey was of about 2000 current medical cannabis users. It’s not surprising they say it works.

Q: So it’s not true?

A: No, I think it quite like is true, or at least partly true — not for everyone, but for a lot of people.

Q: Then what’s the problem?

A: The survey provides almost no additional evidence that it’s true. I already thought it was plausible, but anyone who didn’t think that shouldn’t have had their mind changed by the survey.

Q: Ok, what would convince you? Do we need randomised trials?

A: That would be nice.

Q: And a pony?

A: Ok, ok.  More realistically, a cohort study that follows up a group of people starting to use cannabis for pain relief to find out what they end up preferring, rather than starting with people who prefer cannabis.  You could set that up somewhere were medical use was just being legalised, and it wouldn’t cost that much.

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 118 matches played, 71 of which were correctly predicted, a success rate of 60.2%.
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.

• A map of 1.3 billion taxi trips in New York, taking advantage of the underappreciated principle that there’s no point having more detail than the screen can display.  Also, GPS error naturally gives an attractive glowing effect that you’d usually have to add in afterwards

• “In the summer of 2015, Alexandra Franco got a letter in the mail from a company she had never heard of called AcurianHealth. The letter, addressed to Franco personally, invited her to participate in a study of people with psoriasis, a condition that causes dry, itchy patches on the skin.”  A story about creepy data-mining, from Gizmodo.

• From Scientific American, graphics showing daily, weekly, yearly patterns in number of births.

• From the New York Times: a new drug for muscular dystrophy. It costs about US$1 million per year, and the FDA is not really convinced it has an effect

• It’s time for the NZ Garden Bird Survey, which means it’s time for me to recommend their questions and answers page for its attention to principles of experimental design.

• “Death when it comes will have no sheep”. Last week it was hamster names; this week it’s proverbs. Look, save yourself some effort and just go directly to Janelle Shane’s blog rather than waiting for each post to go viral.

• “In Science, probability is more certain than you think.” Chad Orzel

I missed this a couple of weeks ago when it came out, but Stuff has a pretty good story on the ‘cheese addiction’ question.

As long-time readers will know, there’s been a persistent story circulating in the media claiming that a University of Michigan study found cheese was addictive because of substances called casomorphins.  The story is always unsourced (or sourced only to another copy), and the researchers at the University of Michigan have pointed out that this isn’t remotely like what their research found. The difference now is that Dr Neal Barnard, of the Physicians Committee for Responsible Medicine is fronting up. He’s written a book.

As the story on Stuff says (with added expert input), the cheese addiction claim doesn’t really stand up, but cheese is high in fat and there are things to not like about the dairy industry. And

While it’s not hard to pick holes in some of Barnard’s anti-cheese arguments, the book has good advice on what to eat instead

That could well be true but, as with paleo, you could find books that just give the recipes and leave out the scientifically-dubious propaganda.

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 111 matches played, 67 of which were correctly predicted, a success rate of 60.4%.
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.

RadioNZ has a new “Healthy or Hoax” series looking at popular health claims. The first one, on coconut oil, is a good example both of what it does well, and of the difficulties in matching the claims and science.

The serious questions about coconut oil are about changes in blood fats and in insulin resistance when saturated fats replace various other components of the diet.  Replacing sugar and starch by  saturated fat is probably good; replacing, say,  monounsaturated fat by saturated fat probably isn’t. But in both cases the effects are small and are primarily on things you don’t notice, like your cholesterol level. That’s why there’s disagreement, because it’s actually hard to tell, given all the individual variability between people.

The superfood questions about coconut oil are about whether eating loads of it makes dramatic improvements in your health over a period of a few weeks.  There’s no reason to think it does, and the story quotes various people including Grant Schofield — who is at one end of the spectrum of respectable views on this subject — as saying so.

That’s all fine, but a big part of the story is about Kate Pereyra Garcia trying it for herself.  If the scientists — any subset of them — are right, a study on one person isn’t going to say anything helpful.  A one-person experience might disprove some of the extreme superfoodie claims, but no-one who believes those claims is likely to pay attention.

So, on one hand, the series looks like a great way to bring up the relatively boring evidence on a range of health topics. On the other hand, it’s reinforcing the concept of individual testimonials as a way of evaluating health effects.  If it was that easy to tell, we wouldn’t still be arguing about it.

• A simulation of measles spreading through communities with different vaccination levels.

• Teaching a neural network to come up with guinea pig names. And with gourmet food ingredients. And metal band names.

• Update on the prosecution of the former government statistician of Greece, Andreas Georgiou, apparently because the right numbers weren’t popular.

• Blind testing suggests wine tasters do much better than chance, but nowhere near as well as they’d like you to think.

• “It’s not that people don’t like Mexican food. The reason was that the system had learned the word “Mexican” from reading the Web.” On reducing the ethnic and gender biases of automated text analysis

• Herald Insights visualisation of crime patterns in New Zealand. Yes, there’s a denominator problem; no, the obvious fixes wouldn’t help.

Dealing with uncertainty – see how different the models are for Tuesday night. This is why just taking the average doesn’t always work! ^TA pic.twitter.com/YdtEzpaKwI

— MetService (@MetService) June 9, 2017