The best law-of-large-numbers scene in modern cinema.
“A spectacular vindication of the principle that each individual coin, spun individually, is as likely to come down heads as tails, and therefore should cause no surprise each individual time it does”
Today (in NZ) is the summer solstice, the time when the sun is the highest in the sky, and the longest day. In the northern hemisphere it’s the winter solstice, the darkest day of winter.
The date of Christmas, as every school child knows, wasn’t even in theory chosen as the anniversary of a particular night when shepherds were abiding in the fields. Views differ on whether it was chosen to match the Roman solstice celebration on December 25th, or nine months after the equinox on March 25th. In either case, though, we seem to be off by a few days. Today is the solstice and nine months after the equinox, but Christmas isn’t until Thursday. Why could that be?
One possibility, advanced by German historian Heribert Illig, is that the date isn’t really 2014 this year. It’s really only 1717, so we haven’t had enough missing leap years since the year 1 CE and the Gregorian calendar is off by a few days. That is, according to Illig, the period from 614 CE to 911 CE didn’t happen. The evidence adduced for this gap, in addition to the date of Christmas, is a shortage of buildings in Constantinople (now Istanbul) in that period, and a gap in Christian theological development.
Back in consensus reality, the Phantom Time Hypothesis provides a nice illustration of how data in different fields interlocks like a crossword puzzle. For example, the times of historical eclipses and sightings of Halley’s Comet match the standard calendar, and don’t match if you assume there are three missing centuries, and the same is true of tree ring counts, and the last big eruption at Lake Taupo. And while the history of Rome and Constantinople is arguably tidier in some ways, there’s a hole blown in the middle of the Tang Dynasty, including important events such as the Battle of Talas.
So, is there a better explanation of why today isn’t Christmas? In fact, yes. When the Gregorian calendar was devised, it didn’t try to go all the way back to 1CE, which people already realised was a slightly iffy date at best. It was designed to match the Julian calendar in 325CE: the date of the Council of Nicea, when the formula for the date of Easter was agreed on (and where Nicholas of Myra, aka Santa Claus, was thrown in jail for slapping Arius during a debate)
StatsChat wishes you a happy summer or winter solstice. Try to refrain from slapping anyone, whatever the provocation.
A good story in the Herald about a potentially-important randomised trial conducted in New Zealand.
There’s an anti-smoking pill that was first produced in Bulgaria in 1964, using cytisine, a toxin found in several trees and bushes of the pea family (including common broom and kōwhai). Cytisine is a partial agonist for the same receptors in the brain that nicotine targets. At the right dose, it keeps nicotine away from the receptors and turns them on, but not all the way. The net effect is that it reduces nicotine craving but isn’t actually enjoyable. The New Zealand trial found offering cytisine was superior to offering nicotine patches or gum for people recruited through Quitline.
Cytisine is similar in mechanism to the much-newer drug varenicline (Champix in NZ, Chantrix in USA). In fact cytisine was the starting point for the development of varenicline, and while the newer drug is superior in some lab tests involving rats, I don’t think they have ever been directly compared in humans.
The disadvantage of cytisine is that it’s less thoroughly studied than varenicline, so less is known about its rare side effects (yes, it was used in communist Europe, but personally I wouldn’t give much for their population mental health data). The quoted advantage in the Herald story is that it’s much cheaper than alternatives: about a dollar a day. That’s not entirely compelling, since Pharmac pays only $2.40/day, but the price advantage might be more relevant in Brazil or India for the four years left on the varenicline patent.
The other advantage given by the researchers (though not in the Herald story) is more interesting. Because cytisine is a natural product, and because it is present in kōwhai (although that isn’t and wouldn’t be the commercial source), they thought it might be more acceptable to Māori as something that would fit into traditional healing practices (rongoā). The idea was supported by a study involving semi-structured interviews with people identifying as Māori.
Clearly, kōwhai wasn’t traditionally used to treat tobacco addiction, since tobacco addiction wasn’t traditionally a problem. No-one’s suggesting that cytisine should be advertised as actually traditional, and the scenario in the interview was that the drug would only be used if there was proper scientific evidence of safety and effectiveness. This isn’t ‘traditional use’ as a substitute for evidence; it’s traditional use as affiliation.
Q: Did you see that pregnant women are supposed to stop wearing lipstick now?
A: <sigh>
Q: But didn’t the study find lipstick lowered kids IQ?
A: What study?
Q: Um. This one that was “undertaken in the United States”
A: The United States is a big place. They’re probably doing several studies. Can you be more precise?
Q: <looks frantically for more info in the story> Um, no?
A: Perhaps you mean this paper, which is open access and easily linked.
Q: That looks right. What does it say about lipstick?
A: Nothing. The word “lipstick” doesn’t appear in the paper.
Q: You don’t need to be such a pedant. Do they call it “cosmetics” or “beauty products” or something?
A: Nope.
Q: Ok, so what is the paper about?
A: Mothers with higher exposure to some (but not others) of a class of chemicals called ‘phthlates’ had children with lower IQ scores.
Q: How much lower?
A: The average for the lowest 25% was about 7 points higher than the highest 25%.
Q: Is 7 points a lot?
A: It’s not trivial, but not huge. It’s the difference between the 60th and 40th percentile of IQ.
Q: How much uncertainty is there in that?
A: Good question. The lower limit is less than two points, the upper limit is nearly 12, but that’s assuming there wasn’t any cherry-picking in the analysis.
Q: Where does the research say phthlates come from?
A: “Exposures to phthalates are ubiquitous”. That is, they are everywhere.
Q: Not just in lipstick?
A: No.
Q: Mostly from lipstick?
A: No.
Q: If these pollutants are everywhere, could there be socioeconomic factors that affect exposure? I mean, rich people usually don’t put up with as much pollution as poor people.
A: That’s been looked at, and phthlates are one of the pollutants with environmental justice concerns, though the evidence isn’t clear on whether there’s a general socioeconomic status correlation or just a correlation with minority ethnicity.
Q: So should we worry about phthlates?
A: I don’t know. It’s not clear. It might be a good idea to reduce phthlate use in industrial processes, but it depends on what the alternatives are.
Q: Should we worry about lipstick?
A: Probably not.
Q: Should we worry about newspaper headlines blaming mothers for their children’s problems?
A: You could do worse.
From The Independent
“Although it is common to blame media outlets and their journalists for news perceived as exaggerated, sensationalised, or alarmist, our principle findings were that most of the inflation detected in our study did not occur de novo in the media but was already present in the text of the press release produced by academics and their establishments,” the researchers write in the BMJ.
The study seems to be arguing that press offices are to blame for the spin, not journalists.
Ed Yong, a well-known freelance journalist and science writer, interpreted it differently on Twitter
Blame is not a zero-sum game. If exaggerations or inaccuracies end up in science/health reporting, then the journalist should always take 100% of the blame, even if the errors originated with scientists or press releases. Errors can arise anywhere; they are meant to end with us. We are meant to be bullshit filters. That is our job
It can be a hard job, with many systemic factors—editorial demands, time pressures, lack of expertise—that stop us from doing it properly. These are reasons for empathy, but they change nothing. If we publish misleading information, and try to apportion blame to our sources, we implicitly admit that we are mere stenographers—and thus useless. If we claim to matter, we must take blame.
I’d agree the blame isn’t zero-sum, and I think the scientists also deserve a lot of it. Ben Goldacre has previously suggested that press releases should bear the name of one of the researchers as a responsible person and should appear in the journal next to the paper (easy for online journals).
In a way, the press offices of the universities and journals are the only people not really at fault, even if most of the spin originates there. They are the only people involved without a professional responsibility for getting the story accurate and in proportion. Making lemonade out of lemons is their job.
I would link to the paper and to Ben Goldacre’s commentary in the BMJ, but it isn’t available yet. You can read the Science Media Centre notes, which are based on the actual paper. The journal seem to have timed their media information releases so that there is plenty of media commentary and online discussion without the facts from the research being available.
The irony, it burns.
[Update: research paper is now available]
[Further update: and the research paper puts the blame more clearly on the researchers than the story in the Independent does — see comments]
A very nice interactive game and simulation by Vi Hart and Nicky Case, showing how very high levels of segregation can result even from just a preference for not being overwhelming outnumbered.
On the positive side, a fairly small active preference for diversity can overcome this problem.
