Posts filed under General (3156)

One of my favorite ambiguously-hyphenated phrases, but in this example the hyphen definitely goes after the second word.

The Herald tells us (or reprints the Daily Mail telling us):

Children who eat junk food will grow up to have a lower IQ than those who regularly eat fresh, home-cooked cooked meals, a study reveals.

Childhood nutrition has long lasting effects on IQ, even after previous intelligence and wealth and social status are taken into account, according to the paper.

 You’d think from that description that the study looked at children growing up, and that they found effects of meals in the past rather than the present. And that the effects were big.  None of these is the case.

The paper (paywalled) looked at cognitive function tests and meals at ages 3 and 5 for a group of children.  The analysis found that 5-year IQ was related to meals at age 5, but not (or more weakly) to meals at age 3, and, to quote the researchers themselves

 Overall, having more often slow meals accounted for negligible amounts of variance in cognitive change.

where `negligible’ means less than 1%.

You’d also worry about other differences between families that might be associated with IQ-test performance.  The quote tells us that previous intelligence and wealth and social status were taken into account, but the ‘wealth and social status’ in the statistical models was just a single five-point scale, and there’s no way that could reliably account for socio-economic differences.

Things that save lives often cost money, and governments and individuals around the world need to decide how much they are willing to give up in order to save one life or prevent one serious injury.  These decisions imply some value for a death prevented, and under some moderately unrealistic assumptions about how people think, you could argue that the implied values should be consistent for different decisions, giving us social costs of various policy issues.

But if you are going to say, as Stuff quotes Godfrey Bridger saying

“There’s also the enormous saving in human suffering and misery which isn’t captured in these statistics. A national road lighting upgrade is a no-brainer.”

you can’t also quote costs that do ‘capture the human suffering and misery’, such as

the estimated $1.2 billion annual cost of night-time road deaths and injuries.

The estimated $1.2 billion annual cost is for 61 deaths and 1538 injuries on the roads at night.  It’s immediately obvious that these can’t be actual cash costs — nearly a million dollars per injury — so they must include some sort of value of a life.  It’s less clear whether they also include physical and emotional pain from injuries, but if they don’t, the estimated value of a life lost must be very high.  This is one the journalists should have caught: the basic journalism rule for numbers is “if you have two numbers, do something with them”. In this case, divide them.

You can either separate out monetary and non-monetary costs, on the grounds that different people weigh them differently, or combine them, on the grounds that government spending should treat all lives the same, but you can’t have it both ways.

….but why?

The Herald passes on figures from a

New Zealand is overweight – collectively the adult population weighs more than 232,000 tonnes.

But while New Zealand accounts for only 0.08 per cent of the total weight of the world adult population, it makes up 0.22 per cent of the world’s excess weight due to obesity, according to a new study.

It makes sense to talk about NZ having more than its share of carbon emissions, because this is a global resource that is valuable to everyone.  Obesity, not so much. Alternatively, it could make sense if there was a linearly increasing health risk with weight, but again there isn’t: there’s a broad low-risk region with health risks increasing dramatically at higher or lower levels.

The Herald website front page asks

New Zealand has been allocated 2000 of the 10,000 places available for the 2015 dawn service at Gallipoli – guess which country gets the rest?

The guess isn’t that hard, and the allocation seems pretty fair to NZ.  Australia gets 4 times as many places. It has 4.9 times as many people now, had 5.9 times as many serving in the campaign, and 3.7 2.2 times as many died.

Intrade is a company that hosts betting on political events, to “tap the wisdom of crowds”.  Matthew Yglesias posted the graph below, which shows the difference between the Intrade betting percentage on “Barack Obama wins the presidential election” and “The Democrats win the presidential election”.

The spikes above zero could theoretically just about be rational — if Obama dies before the election, the Democrats could win without Obama winning — although a probability of even 1% of this seems too high.  The spikes below zero imply that Obama wins without the Democrats winning, which really isn’t conceivable.  If you bet against the Democrats winning and in favor of Obama winning (or vice versa) at the right times you could make guaranteed free money.

The problem is that Intrade is small enough that it’s not worth people with lots of money hanging on it trying to exploit minor irrationalities, even for big events like the presidential election, especially when you take transaction costs into account. Betting markets tend not to leave $20 notes lying on the table, but they can drop the occasional handful of change.

….and the bartender asks them if they need help setting up for their talks.

The second episode of Nerdnite Auckland is on Tuesday October 2, at Nectar, in Kingsland (if you have trouble finding it, it’s upstairs, above the Kingslander). Presumably it starts at closer to 6:30 this time, since the bugs should have been worked out of the system.

Also, on Wednesday September 26, Cafe Scientifique is on at the Horse and Trap, with Gillian Turner, from Vic Uni Wellington, talking: “Flips and Wiggles — the mystery of Earth’s magnetism”.  They recommend arriving at 6ish for a 6:30 start to the formalities.

There’s a new paper in the journal PLoS One (free access), looking at what research makes the news.

We focused on attention deficit hyperactivity disorder (ADHD). Using Factiva and PubMed databases, we identified 47 scientific publications on ADHD published in the 1990s and soon echoed by 347 newspapers articles. We selected the ten most echoed publications and collected all their relevant subsequent studies until 2011. We checked whether findings reported in each “top 10” publication were consistent with previous and subsequent observations. We also compared the newspaper coverage of the “top 10” publications to that of their related scientific studies.

The media are more likely to report the more surprising findings; these are more likely to be wrong.  The relatively boring research that contradicts these findings doesn’t get reported, because it would put people to sleep.

To a lesser extent the same bias is found in the scientific literature.  If you find something surprising and dramatic, you’re more likely to work nights and weekends to get it written up, and to submit it to a top journal.  Research with methodologic problems is more likely to get past peer review if it’s interesting than if it’s boring.

In the case of clinical trials this publication bias has been recognised as a clear and present danger to patient care, and steps have been introducted to reduce its impact.   More generally it’s hard to see what to do in the scientific literature: we don’t actually want a lot of boring low-quality research in academic journals (we have to read them, after all), and we don’t want to suppress interesting findings because the research wasn’t perfect.

For newspapers, a bit more restraint in  scientific press releases would help.  The philosopher Daniel Dennett had a nice phrasing of this. I don’t remember it exactly, but it was along the lines of “Preliminary scientific results should be treated like any other potentially hazardous laboratory waste and not irresponsibly discharged into the environment”

The Herald tells us that slang and texting are responsible for children not being able to write.

This is one of the topics that Language Log can handle better than StatsChat, so I’ll direct you there for a dismantling of the theory:

• Texting and language skills
• Shattering the illusions of texting

Otago-born Len Cook was the Director of the Office for National Statistics in the UK from 2000-2005. He also served as Registrar-General of England and Wales and in that role got to decide that Prince Charles and Camilla’s marriage could proceed. Prior to that he spent nearly 30 years at the Department of Statistics in New Zealand, holding the top post of Government Statistician from 1992 to 2000. On Nine to Noon yesterday

For anyone who wants to read more coverage

• Herald
• 3News
• Scoop

• NY Times (a generally good source on science)
• New Scientist
• The Age
• BBC (update)
• Los Angeles Times (update)

• UK Science Media Centre
• NZ Science Media Centre
• Australian Science Media Centre

I thought I saw a Stuff story, but I can’t find it now.

Update: Ivan Oransky, of Embargo Watch, has found more sources to confirm the dodgy embargo and has a post on it.