## Occasional reflections on Life, the World, and Mathematics

### Parliamentary mortality

An article in the New Statesman raised the question of whether the Conservatives could lose their hold on power via by-elections over the next few years only to dismiss the possibility because by-elections simply don’t happen frequently enough. The reason? Reduced mortality rates. Quite sensible, but then this strange claim was made:

In 1992-7, the last time that the Conservatives had seven by-elections in a parliament, life expectancy was 15 years lower than it is today.

Ummm… If life expectancy had increased by 15 years over the last 20 years, we’d be getting close to achieving mortality escape velocity. In fact, the increase has been about 5 years for men and 4 years for women.

But that raised for me the somewhat morbid question: How many MPs would be expected to die in the next 5 years? Approximate age distribution of MPs is available here. It’s for the last parliament, but I’ll assume it remains pretty similar. It’s interesting that Labour had twice as large a proportion (25% vs 12%) in the over-60 category. In addition, I’ll make the following assumptions:

1. Within coarse age categories the distribution is the same between parties. (This is required to deal with the fact that the numbers by party are only divided into three age categories.)
2. Since I don’t have detailed mortality data by class or occupation, I’ll simply treat them as being 5 years younger than their calendar age, since that’s the difference in median age at death between men in managerial occupations and average occupations.
3. I assume women to have the same age distribution as men.
4. I’m using 2013 mortality rates from the Human Mortality Database.

My calculations say that the expected number of deaths over the next 5 years is about 6.4 Conservatives and 6.5 Labour. So we can estimate that the probability of at least 7 by-elections due to deceased Tory MPs is just a shade under 50%.

### The secret to a long life

It’s well known that marriage is an important factor in longevity. But maybe we’ve been interpreting that wrong, or, at least, not optimising.

From the Gerontology Research Group article on the current oldest living person, Italian Emma Morano:

In 1926, Mrs. Morano was married to Giovanni Martinuzzi, a marriage she would rather not talk about… Having separated – but not divorced – from her husband in 1938, Mrs. Morano has lived alone ever since, and accredits this as one of the key secrets to her longevity.

### Absence of correlation does not imply absence of causation

By way of Andrew Sullivan we have this attempt by Philip N. Cohen to apply statistics to answer the question: does texting while driving cause accidents? Or rather, he marshals data to ridicule the new book by Matt Richtel on a supposed epidemic of traffic fatalities, particularly among teens, caused by texting while driving. He has some good points about the complexity of the evidence, and a good general point that people like to fixate on some supposed problem with current cars or driving practices, to distract their attention from the fact that automobiles are inherently dangerous, so that the main thing that causes more fatalities is more driving. But then he has this weird scatterplot, that is supposed to be a visual knock-down argument:

We need about two phones per person to eliminate traffic fatalities…

So, basically no correlation between the number of of phone subscriptions in a state and the number of traffic fatalities. So, what does that prove? Pretty much nothing, I would say. It’s notable that there is really very little variation in the number of mobile phones among the states, and at the lowest level there’s still almost one per person. (Furthermore, I would guess that most of the adults with no mobile phone are poor, and likely don’t have an automobile either.) Once you have one mobile phone, there’s no reason to think that a second one will substantially

Whether X causes Y is a separate question from whether variation in X is linked to variation in Y. You’d like to think that a sociologist like Cohen would know this. A well-known example: No one would doubt that human intelligence is a product of the human brain (most directly). But variations in intelligence are uncorrelated with variations in brain size. (Which doesn’t rule out the possibility that more subtle measurements could find a physical correlate.) This is particularly true with causes that are saturated, as with the one phone per person level.

You might imagine a Cohen-like war-crimes investigator deciding that the victims were not killed by bullets, because we find no correlation between the number of bullets in a gun and the fate of the corresponding victim.

Just to be clear: I’m not claiming that evidence like this could never be relevant. But when you’re clearly in the saturation region, with a covariate that is only loosely connected to the factor in question, it’s obviously just misleading.

### Moral panic panic: How much ridicule are the lives of 4500 children a year worth?

As though it need to defend its title as the world’s leading provider of smug, The New Republic has published a piece by NY Times religion reporter Mark Oppenheimer (MO hereafter) about how irrational everyone is. This disturbs him, because when he was growing up, when all was right with the world, “It was taken for granted in my house… that only right-wingers were mad enough to oppose scientifically tested public-health measures.” He describes what he calls “The New Puritanism”, starting from opposition to water fluoridation in Portland (which doesn’t look like an archetypically puritanical cause to the untrained eye), and moving on to Kids Today:

At a birthday party for a three-year-old, I was hit with the realization that most of the parents around me were in the grip of moral panic, the kind of fear of contamination dramatized so well in The Crucible. One mother was trying to keep her daughter from eating a cupcake, because of all the sugar in cupcakes. Another was trying to limit her son to one juice box, because of all the sugar in juice. A father was panicking because there was no place, in this outdoor barn-like space at some nature center or farm or wildlife preserve, where his daughter could wash her hands before eating. And while I did not hear any parent fretting about the organic status of the veggie dip, I became certain there were such whispers all around me.

Now, this could be dismissed as a dreary attempt to channel PJ O’Rourke, or some comparable swaggering humourist, with a cookie-cutter tall tale, but it’s stuffed with all kinds of weird. He hallucinates “whispers all around” about the organic status of the veggie dip, and yet he insists it is the others whose mental stability is in doubt. With that in mind, one might suspect that the father was not “panicking”, but was simply asking where his daughter could wash her hands before eating, which was certainly the custom when I was a child, though perhaps not in Oppenheimer’s antediluvian childhood.

He cites The Crucible, presumably both as a touchstone of left-wing right-thinking and as a marker of his own cultural sophistication, but has clearly never read or seen it. While “witchcraft” are often taken as a metonym for fear of moral contamination, Miller’s play dramatizes political manipulation of mob psychology.

But putting aside MO’s paranoid-pretentious MO, I am fascinated by his comments

When I was a child, birthday parties involved cake, ice cream, and Chuck E. Cheese pizza, or pizza-like substance; and trips to the grandparents’ house involved root-beer floats and late-night viewings of Benny Hill with my grandfather, who liked the T&A humor. I never washed my hands before I ate. And I turned out splendidly.

So, we started with fluoridation of water, which is a “scientifically tested public-health measure” that only a crazy person could oppose, but washing hands before eating — at a “barn-like space” where, presumably, it is not absurd to suppose the children may have been exposed to animal feces — is the kind of over-the-top fear of moral contamination (not just bacterial contamination) that invites mockery.

Now, MO’s aforementioned paranoid delusions may cause one to question his splendid self-appraisal, but he is certainly not alone in trumpeting the formulation “When I was a child we all did X, and we all turned out alright,” where X is some dangerous or unedifying activity that educated middle-class parents today try to limit or eliminate. An extreme version is this text that got forwarded to me a few years back:

To Those of Us Born 1930 – 1979

First, we survived being born to mothers who smoked and/or drank while they were pregnant. They took aspirin, ate blue cheese dressing, tuna from a can and didn’t get tested for diabetes. Then after that trauma, we were put to sleep on our tummies in baby cribs covered with bright colored lead-base paints. We had no childproof lids on medicine bottles, locks on doors or cabinets and when we rode our bikes, we had baseball caps not helmets on our heads. As infants & children, we would ride in cars with no car seats, no booster seats, no seat belts, no air bags, bald tires and sometimes no brakes. Riding in the back of a pick- up truck on a warm day was always a special treat. We drank water from the garden hose and not from a bottle. We shared one soft drink with four friends, from one bottle and no one actually died from this. We ate cupcakes made with Lard, white bread, real butter and bacon. We drank FLAV-OR- AID made with real white sugar…. We fell out of trees, got cut, broke bones and teeth and there were no lawsuits from these accidents. We would get spankings with wooden spoons, switches, ping pong paddles, or just a bare hand and no one would call child services to report abuse…

You might want to share this with others who have had the luck to grow up as kids, before the lawyers and the government regulated so much of our lives for our own good. While you are at it, forward it to your kids so they will know how brave and lucky their parents were. Kind of makes you want to run through the house with scissors, doesn’t it?

The implication is that the kids are all softies and the parents are anxious killjoys. I heard a stand-up comedian a few years back complaining about bicycle helmets: “When I was a kid we all fell off our bikes. We didn’t fall on our heads. If we did, no one died. Have kids’ heads gotten softer?”

Except, of course, that it’s not true that no one died. This is a good example of how people deal with small risks: Some are treated as zero, others are exaggerated. And part of the phenomenon (though I’ve never seen anyone analyse this process in detail) is that people fixate on whatever the current largest risks are, and often succeed in pushing them down. At that point, a new danger pops up that was always there, but masked by a larger risk, and so psychologically zeroed out. Thus, when I was growing up, in the 1970s, public health officials weren’t very concerned with children’s head injuries from bicycle accidents because there were far more of them from automobile accidents in the absence of seat belts, not to mention all the poisonings from medications without child-resistant packaging. If the risk of dying

To put some numbers on it: In the US, in 1998, about 6500 children under the age of 15 died in accidents. In 1981 (the earliest year whose statistics I have easily available at the moment) the number was 9000. In that time, the population under 15 increased from 49 to 60 million. In other words, if the society had held onto its habits of eschewing bicycle helmets, leaving the medications out, riding in the back of a pickup truck and all the rest, we’d have more than 4500 extra dead children a year. How awesome would that be?

That’s not to say that all concerns about health and nutrition and environment are reasonable — or that, even if they are reasonable, that the actions one would take to prevent or mitigate harm would not impose considerable costs, even such that they might be judged to outweigh the benefits. But instead of mockery and “I turned out alright” populism, we need to be clear on what the benefits are: 4500 fewer children being buried every year. And that’s ignoring the costs of nonlethal sickness and injury, the extra miscarriages and stillbirths, and the long-term damage to lungs and other organs that we now know were caused by all those smoking and drinking parents.

Update: The comedian I was thinking of was a woman, but here’s another comedian making fun of bicycle helmets for emasculating our children; in this version, he’s not asking why heads got softer, but why the pavement is harder. Same joke.