Occasional reflections on Life, the World, and Mathematics

Posts tagged ‘demography’

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.

Being demographic

People have been saying for a long time that the Republican strategy of ethnic nationalism is running out of room, because of increasing proportions of ethnic minorities. I noted during the 2012 election how odd it was that some groups of people were considered to vote “demographically”, while others (white Protestant men) were assumed to vote on the basis of a broad array of concerns. According to the demographic fallacy, minority groups have special interests that are very important to them, but only of peripheral interest to the majority. Too much pandering can piss off the majority, but targeted appeals can motivate the minority, potentially to very high percentages, but there is no way to motivate the majority en bloc. After the 2012 election there were any number of comments of the sort “To win the presidency, Republicans need to make up their deficit among black and hispanic voters. They are losing them at such a level that (with changing povulation composition) a future Republican candidate would need to win the white vote at implausible levels to win a majority.” Now it appears that this argument is exactly wrong, for three reasons:

  1. As Trump correctly intuited, white people are also susceptible to ethnic appeals. And if you can motivate them as an ethnic group, they’re the biggest, baddest one of all. Meanwhile, the Democrats appeal to ethnic minorities was maxed out. The pervasive undercover racism of the Republican party gave Obama a huge edge among hispanics and blacks; naked racism, religious exclusion, and threats of deportation by Trump couldn’t move it any further, but could pull in vast numbers of white voters who share his racist world view and are relieved to hear it expressed openly. Those of us who move in educated circles should have taken more seriously the assertions early on that “Trump says what everyone really thinks”. Obviously, we didn’t know what people were thinking.
  2. Similarly for women. The model of what I called “demographic thinking” in politics is  I’m not the first to notice that women are not actually a minority. The power relations (yay intersectionality!) nonetheless seem to justify seeing the struggle for women’s rights as analogous to the struggle for rights of ethnic minorities.
    Feminists may have gotten suckered by a figure-ground second-sex fallacy with regard to women voters. If you think of males as the default, and women as the “minority”, then an openly misogynist candidate like Trump would seem to turn out the women to vote against him. But most of those women have been having to compromise with and make excuses for Trump-like figures in their lives — in their families — their whole lives. Some will recoil in horror, but most will continue to make excuses. And the women voters lost may be balanced by just as many men gained.
  3. It’s perfectly possible to maintain a semblance of democracy while entrenching the power of a minority to rule over the majority. Many countries have done this. With the single exception of 2004, the Republicans have not won a plurality in a presidential election since 1988. Democrats received a majority of the votes for representatives in 2012 and (probably) 2016. Nonetheless, the Republicans have attained unrestricted control over nearly the entire federal government, and very little stands in the way of further restricting voting rights to maintain their control and civil rights of minorities, expanding the political influence of the wealthy, to maintain their power indefinitely.

The electoral college was designed to leverage the 3/5 compromise to increase the power of southern slave-holding states in presidential election. Now, under very different circumstances, it is still serving this function.

Primary sex ratio, the short version

Five months after our article with Orzack et al. appeared in PNAS, showing that the primary sex ratio (the fraction of boys conceived) is close to 50%, contradicting centuries of supposition that it was substantially higher (more male-biased), Bill Stubblefield, Jim Zuckerman and I have published a popular account of the research in Nautilus. It was an interesting experience, the back and forth with an editor to make something comprehensible and gripping for a general audience.

I didn’t end up exactly as we would have liked, but it was probably better — as an effort to explain the science and the background to a general audience — than what we would have produced entirely on our own. The layout and graphics are also very well done.

It’s now been condensed down to three paragraphs on Gizmodo. They even condensed the illustration.

Prenatal sex ratio

A paper that I’ve been involved with for a dozen years already has finally been published. We bring together multiple data sets to show that the primary sex ratio — the ratio of boys to girls conceived — is 1, or very close to 1. Consequently, the fact that more boys than girls are born — the ratio is about 1.06 pretty universally, except where selective abortion is involved — implies that there must be a period in the first trimester when female embryos are more likely to miscarry than male.

This is one of those things that is unsurprising if you’re not an expert. The experts had developed something close to a consensus, based on very little evidence, that the sex ratio at conception was much higher, some saying it’s has high as 2 (so that 2/3 of the conceptuses would be male), with excess female mortality throughout gestation. (We know that male mortality is higher in the second half of pregnancy, and after that… forever.)

The paper has its problems, but I think it’s a useful contribution. It’s also the first time I’ve been involved in research that is of any interest to the general public. Several publications have expressed interest, and an article has already appeared in two German magazines online, including the general news magazine Der Spiegel.

Update: Guardian too. This makes it interesting, in retrospect, that we had such a hard time getting a journal even to be willing to review it. One said it was too specialised.

Are you demographic? part 2

I was just eavesdropping on a conversation by a notorious American expatriate Republican, who likes to preach to the heathens British. I can see the appeal for both sides: He gets to spool out superficial right-wing talking points without being challenged, because his interlocutor has no sense of the details; and the Brits feel like they’re hearing some inside dope that sounds entirely different than the line they get from the British press. For instance, America is two nations — coasts and interior (presumably the Great Lakes count as oceans for this purpose) — and that the liberal coastal states are about to sink under the weight of their unfunded mandates

So the future belongs to heartland Republicans, and one reason, he explains, is that the liberal Babylon is losing population to the right-thinking interior. This isn’t entirely true: West coast states are all growing at above-average rates, as are Maryland and Delaware. It’s mostly the industrial Midwest that’s sinking. But the argument is based on an assumption that geography is destiny. Growing the demographic power of staunchly Republican states is not the same thing as growing the demographic power of Republicans.

People don’t adopt the political colours of their new homes (as this fellow should surely understand) rapid growth of North Carolina and Virginia, for example, has been linked to migration from less conservative regions, and to urbanisation, both of which have converted reliably Republican-voting states into Democratic-leaning ones. Population growth in Florida, Texas, Colorado, and Nevada has been cited by many experts as harbingers of future Democratic strength, as much of the increase is coming in Hispanic populations, who have shown much higher affinity with the Democrats.

(The habit of describing ethnic minority voters as being demographically determined was the target of my previous Are you demographic? post.)


James Joyce on demography

I’ve been listening to Donal Donnelly’s wonderful recorded reading of Ulysses, and naturally both the format and my advancing years have highlighted passages that didn’t interest me when I read it in my teens and 20s. In particular, there is the unceasing drumbeat of birth and death: hundreds and hundreds of references, only the most prominent of which are, on the death side, Stephen Dedalus’s mother and Leopold Bloom’s son Rudy, and Paddy Dignam, whose funeral Bloom attends; and on the birth side, Mina Purefoy’s agonising three-day labour. Of course, you can’t miss it, but I didn’t notice the big picture. In particular, I didn’t notice how Bloom keeps circling from the individual death to the population level — what one might call the demographic perspective — and back again. (I also had forgotten how much time Bloom spends reflecting on scientific matters generally.) He has thoughts like

Funerals all over the world everywhere every minute.

Child born every minute somewhere.

and most impressively

Mina Purefoy swollen belly on a bed groaning to have a child tugged out of her. One born every second somewhere. Other dying every second. Since I fed the birds five minutes. Three hundred kicked the bucket. Other three hundred born, washing the blood off, all are washed in the blood of the lamb, bawling maaaaaa.

Cityful passing away, other cityful coming, passing away too: other coming on, passing on. Houses, lines of houses, streets, miles of pavements, piledup bricks, stones. Changing hands. This owner, that. Landlord never dies they say. Other steps into his shoes when he gets his notice to quit. They buy the place up with gold and still they have all the gold. Swindle in it somewhere. Piled up in cities, worn away age after age. Pyramids in sand. Built on bread and onions.

This sheds some light on the telegram that Stephen recalls early on, with its famous misprint: “Nother dying come home father.” It’s not just a misprint. “Nother” is one letter away from “Mother”, the person he should care about most in the world. But it’s also one letter away from “another”, that is, just another one in an endless sequence of humans dying. And many people are appalled that he seems to have treated his own dying mother as just an instance of a principle.

(The Gabler “corrected edition” appeared in 1984, right around the time I was first reading Ulysses, and so I recall that the press coverage of this publishing event emphasised a few obviously significant emendations, in particular this one, where editors had consistently  corrected the telegram misprint back to “Mother”, thus making a complete hash of the scene since it was impossible to understand why Stephen said that the telegram was a “curiosity to show”. But even then the thematic significance eluded me.)

American exceptionalism: Harassing tourists and others

A discussion broke out on The Dish about the high-handed and sometimes abusive treatment that foreigners entering the US are subjected to, even citizens of international peers, like the EU, compared with the treatment that Americans (and others) receive entering most European countries. All foreigners entering the US are, by law, treated as “an intending immigrant” when they arrive, and need to prove otherwise. Now, a former immigration official has replied with a justification:

Congress demands by law that every applicant for a tourist visa (or any nonimmigrant visa) be considered “an intending immigrant” until they prove otherwise. With good reason – a lot of them are intending immigrants. Why is it Americans have such an easier time traveling to other countries than citizens of those countries have traveling here? Because Americans go home, that’s why.

Even when US citizens work off the books for a year or two overseas, they almost always wind up coming home. The same can’t be said of most foreigners who come here, even Europeans.

Sounds pretty convincing. But is it true? How would he know? I’m always suspicious of categorical claims like this, even when I make them myself.

How about if we compare the number of people from different countries living abroad. According to the French government, there are 1.6 million French citizens living abroad, so about 2.7% of the population. About 2 million Germans (not counting the 600,000 or so Russians who are officially considered “Germans” by ancient descent), so about 2.5%. And Americans? According to the Bureau of Consular Affairs (part of the State Department) there are 7.6 million Americans living abroad. Divided into a population of 316 million, we get about 2.4%. Even if some of these estimates are off, it’s clearly not a qualitative difference.

Sorry, America, the world just isn’t as into you as you like to imagine.

Christmas Demography

Whereever I have lived in my adult life, the city has been extraordinarily quiet from Christmas to New Year’s — indeed, the quiet starts somewhat before Christmas. The natural explanation is that people go away for the holidays. (Students obviously do, but it’s far quieter than even at other times when students are on vacation.) The problem is, they must go somewhere, so it can’t be that every place empties out. (Obviously, some of the apparent quiet is simply the absence of traffic from people going to work, shopping, etc. When shops and restaurants close down in late December because of lack of customers it’s a bit self-fulfilling.) So why is it that I’m always in the places that people flee for the holidays?

A common pattern is that younger people with children travel to their parents, in their old home towns. In general, if there is a pattern of migration from some places X to other places Y, the sort of people who move around (like myself) will tend to be living at Y. At Christmas, then, the migration is temporarily reversed, and people travel from Y to X. For a brief time, Y empties out and X gets full.  (Even 2000 years ago Joseph and Mary had to go back to their home town for Christmas. And, as we know, the town was full up.) So, people like me notice that whereever they happen to be living is one of the places that empties out, because of the selection bias. People of my parents’ generation are generally living in places that take in visitors at Christmas, and so perhaps seem livelier than at other times of the year.

The demography of evil…

… or the evils of demography?

I wrote a while back about my concern, as a sometime demographer, about how the word “demographic” had been transmuted, by some offbeat associations, in the language of US electoral politics, into a euphemism for what might more plainly be called “ethnic or religious minorities”.

Max Blumenthal’s book Goliath, which I wrote about here and here, reminded me of another, even more disturbing abuse of the name of a perfectly respectable academic subject: Israel’s obsession with its “demographic time bomb”, what other people might call “Arab citizens”.

I just checked Google’s completions for a snapshot of the mass mind: Indeed, if you type “Israel demograph”, the first two completions that Google offers are “Israel demographic time bomb” and “Israel demographic threat”. (I’m not blaming anyone for this directly. There’s no way to know who did all those searches. But obviously they were inspired, directly or indirectly, by official Israeli messaging on the issue. “Demographic time bomb” is not a form of words that one would expect to arise spontaneously.)

But the third most popular search term alludes to the point that I would want to make: “Israel demographic transition”. If Blumenthal is to be believed — and while his account is certainly consistent with other reports I have read, I do not consider myself to be sufficiently informed to judge — respectable debate in Israel on the Arab question runs the gamut from “expel them all” to “pressure them to leave the country voluntarily”, with the reasonable compromise being to expel some, and pressure most of the rest to leave voluntarily. Only the radical fringe pushes extremist ideas like “kill them all” and “leave them in peace and allow them equality as citizens”.

Anyone with even a passing familiarity with demography knows that the best way to get a population to stop growing is… to make them prosperous. That’s the “demographic transition”, and there don’t seem to be any exceptions. So, if Israeli Jews were really worried that higher Arab birthrates will eventually make the Jews a minority, they might have chosen to desist from their policies of trying to impede Arab economic activity and make Arab life in Israel a misery — something I first learned about from the fascinating book Separate and Unequal: The Inside Story of Israeli Rule in East Jerusalem, by former insiders in the Jerusalem municipal government — and instead shower them with economic subsidies.

I suspect that there is some willful ignorance behind this promotion of the “demographic threat”. The Palestinians, in this view, aren’t like normal people, who would respond to prosperity with lowered birthrates.

The mistimed death clock: How much time do I have left?

Someone has set up a macabre “death clock“, a web site where individuals can enter a few personal statistics — birthdate, sex, smoking status, and general level of optimism, and it will calculate a “personal date of death”, together with an ominous clock ticking down the seconds remaining in your life. (For Americans, ethnic group is a hugely significant predictor, but I’m not surprised that they leave this out. Ditto for family income.) It’s supposed to be a sharp dose of reality, I suppose, except that it’s nonsense.

Not because no one knows the day or the hour, though that is true, but because the author has built into the calculator a common but elementary misconception about life expectancy, namely, that we lose a year of expected remaining life for every year that we live. Thus, when I enter my data the clock tells me that I am expected to die on August 6 2042. If I move my birthdate back* by 10 years — making myself 10 years older — my date of death moves back by the same amount, to August 6 2032. If I tell it I was born in 1936 it tells me that my time has already run out, which is obviously absurd.

In fact, every year that you live, you lose 1 year, but gain a proportion a remainder equivalent to the probability that you might have died. Thus, a 46-year-old US man has expected remaining lifespan 33.21 years. He has probability 0.00365 of dying in the next year; if he makes it through that year and reaches his 47th birthday, his expected remaining lifespan is (33.21-1)+.00365 x 32.21 = 32.33 years.** So he’s only lost 0.88 years off his remaining lifespan. In this way, it’s actually possible to have more expected remaining lifespan at an older age than at a younger, if the mortality rate is high enough. Thus, if we go back to 1933 mortality rates, the expected lifespan at birth was 59.2 years. But a 1-year-old, having made it through the 6.5% infant mortality, now has 62.3 years remaining on average.

This is another way of expressing the well-known but still often not-sufficiently-appreciated impact of infant mortality on life expectancy. The life-expectancy at birth for US males is 76.4 years. But that obviously doesn’t mean that everyone keels over 5 months into their 77th year. 60% of the newborn males are expected to live past this age, and a 77-year-old man has 10 remaining years on average.

Of course, these are all what demographers call “period” life expectancies, based on the mortality rates experienced in the current year, and pretending that these mortality rates will continue into the future. Based on the experience of the past two centuries we expect the mortality rates to continue to fall, in which case the true average lifespans for people currently alive — the “cohort life expectancies” will exceed these period calculations — but there is no way to know. If an asteroid hits the earth tomorrow and wipes out all life on earth, this period calculation will be rendered nugatory (but there will be no one left to point that out. Hah!) The true average lifespan of the infants born this year will not be known until well into the 22nd century. Or, if Aubrey de Grey is right, not until the 32nd century.

* Or is it moving my birthdate forward by 10 years when I make it 10 years earlier? Reasonable people disagree on this point! And there’s interesting research on the habits of mind that lead one to choose the metaphor of the stationary self with time streaming past me, or the self moving like a river through a background of time.

** Actually, it’s (33.21-1)/(1-.00365)

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