Saturday, October 30, 2010

Statistics, stories, and their tensions

The New York Times's Opinionator featured an article, John Allen Paulos' "Stories vs. Statistics", that caught my attention. I'll quote at length, if you'll forgive me for that.

[T]he notions of probability and statistics are not alien to storytelling. From the earliest of recorded histories there were glimmerings of these concepts, which were reflected in everyday words and stories. Consider the notions of central tendency — average, median, mode, to name a few. They most certainly grew out of workaday activities and led to words such as (in English) “usual,” “typical.” “customary,” “most,” “standard,” “expected,” “normal,” “ordinary,” “medium,” “commonplace,” “so-so,” and so on. The same is true about the notions of statistical variation — standard deviation, variance, and the like. Words such as “unusual,” “peculiar,” “strange,” “original,” “extreme,” “special,” “unlike,” “deviant,” “dissimilar” and “different” come to mind. It is hard to imagine even prehistoric humans not possessing some sort of rudimentary idea of the typical or of the unusual. Any situation or entity — storms, animals, rocks — that recurred again and again would, it seems, lead naturally to these notions. These and other fundamentally scientific concepts have in one way or another been embedded in the very idea of what a story is — an event distinctive enough to merit retelling — from cave paintings to “Gilgamesh” to “The Canterbury Tales,” onward.

With regard to informal statistics we’re a bit like Moliere’s character, who was shocked to find that he’d been speaking prose his whole life.

The idea of probability itself is present in such words as “chance,” “likelihood,” “fate,” “odds,” “gods,” “fortune,” “luck,” “happenstance,” “random,” and many others. A mere acceptance of the idea of alternative possibilities almost entails some notion of probability, since some alternatives will be come to be judged more likely than others. Likewise, the idea of sampling is implicit in words like “instance,” “case,” “example,” “cross-section,” “specimen” and “swatch,” and that of correlation is reflected in “connection,” “relation,” “linkage,” “conjunction,” “dependence” and the ever too ready “cause.” Even hypothesis testing and Bayesian analysis possess linguistic echoes in common phrases and ideas that are an integral part of human cognition and storytelling. With regard to informal statistics we’re a bit like Moliere’s character who was shocked to find that he’d been speaking prose his whole life.

Despite the naturalness of these notions, however, there is a tension between stories and statistics, and one under-appreciated contrast between them is simply the mindset with which we approach them. In listening to stories we tend to suspend disbelief in order to be entertained, whereas in evaluating statistics we generally have an opposite inclination to suspend belief in order not to be beguiled. A drily named distinction from formal statistics is relevant: we’re said to commit a Type I error when we observe something that is not really there and a Type II error when we fail to observe something that is there. There is no way to always avoid both types, and we have different error thresholds in different endeavors, but the type of error people feel more comfortable may be telling. It gives some indication of their intellectual personality type, on which side of the two cultures (or maybe two coutures) divide they’re most comfortable.

People who love to be entertained and beguiled or who particularly wish to avoid making a Type II error might be more apt to prefer stories to statistics. Those who don’t particularly like being entertained or beguiled or who fear the prospect of making a Type I error might be more apt to prefer statistics to stories. The distinction is not unrelated to that between those (61.389% of us) who view numbers in a story as providing rhetorical decoration and those who view them as providing clarifying information.

The so-called “conjunction fallacy” suggests another difference between stories and statistics. After reading a novel, it can sometimes seem odd to say that the characters in it don’t exist. The more details there are about them in a story, the more plausible the account often seems. More plausible, but less probable. In fact, the more details there are in a story, the less likely it is that the conjunction of all of them is true. Congressman Smith is known to be cash-strapped and lecherous. Which is more likely? Smith took a bribe from a lobbyist or Smith took a bribe from a lobbyist, has taken money before, and spends it on luxurious “fact-finding” trips with various pretty young interns. Despite the coherent story the second alternative begins to flesh out, the first alternative is more likely. For any statements, A, B, and C, the probability of A is always greater than the probability of A, B, and C together since whenever A, B, and C all occur, A occurs, but not vice versa.

It's worth noting that Demography Matters' bloggers are concerned with bridging the gap between statistics and narratives, trying to produce narratives of what's going on in our world that are firmly based on statistics--anecdotes illuminate and animate, yes, but we try to limit anecdotes to those highly specific roles. With my specific educational background--English and Anthropology were my two majors--I may be more inclined to emphasize the power of the narrative. Stories provide useful and--I'd argue--necessary framing, very often inspiring statistical research, explaining it, and showing how and why these statistics are used. Certainly Eurabia or hyperaged societies or explanations for low fertility can't be examined--proven, disproven, whatever--without these narratives. But then, I quite agree you also need empirical evidence. Obviously.

It can be a difficult thing to do. What are your thoughts on the issue?

Wednesday, October 27, 2010

On the problems of an Iraqi census

I've recently written about how the gutting of Statistics Canada's long-form census is an act of little value. Just recently, I came across an argument that made something of a case that it was a very good thing Iraq's unable to undertake a census at all. Reuters described the situation this January.

The long-delayed count, which may shut down the country for two days in October, is also expected to determine how many Iraqis live abroad and how many have been forced to move within Iraq in seven years of war, census chief Mehdi al-Alak said.

The census was postponed for a year over worries it was being politicized. Ethnic groups in contested areas like the northern city of Kirkuk, home to Arabs, Kurds, Turkmen and a valuable part of Iraq's oil fields, opposed it because it might reveal demographics that would undermine political ambitions.

The count could provide answers or create more squabbles in a diverse nation riven by sectarian violence following the U.S. invasion in 2003 and now trying to bolster fragile security gains while deciding how to share out its vast oil wealth. Iraq has the world's 3rd largest crude oil reserves.

The autonomous Kurdish region in the north claims Kirkuk as its own. The census will determine whether Kurds are the biggest ethnic bloc in the city, which could bolster that claim.

It will also find out how many people live in Iraqi Kurdistan, which will define its slice of central government revenues, currently 17 percent. If the census finds Kurds are a greater percentage of the total population, the constitution says the region gets more money, and retroactive payments.

What it won't do, Alak said, is attempt to determine which of the hotly disputed areas belong to whom.

"It is not our business to decide their destiny," Alak, the head of the Central Organization for Statistics and Information Technology (COSIT), said in an interview this week. "We count the people in the province where they live. Deciding the destiny of the areas is the business of the politicians."

The census will be the first to include the Kurdish region since 1987. A 1997 census counted 19 million Iraqis and officials estimated there were another 3 million in the Kurdish north.

The current national population is believed to be "not less than 30 million," Alak said.

The census didn't happen, actually, for the reasons of ethnopolitical rivalry that Joel Wing described at his blog as well as the state's bureaucracy. Foreign Policy's Joost Hiltermann argued that, notwithstanding the census' importance in national planning, the census' failure was good inasmuch questions on ethnicity and language would be too polarizing.

The Iraqi census stands to play a critical role in the country's development. Its data will help in drawing electoral districts, allocating funds, projecting future population growth, and planning education, public health, housing, transportation, and other essential elements of a well-regulated state. Particularly in Iraq, which has witnessed several false starts in reconstruction following the 2003 invasion, having accurate socioeconomic data will be indispensable to sound economic planning.

But there's reason to believe that this census, as it is currently designed, will polarize rather than unify Iraqi society. The problem lies in a question that asks Iraqis to define their ethnicity, aiming to get a sense of how big the country's various ethnic groups are. Although such a question will no doubt provide interesting information for academics and analysts, it is not in Iraq's national interest and risks destabilizing some of Iraq's most sensitive hot spots.

The ethnicity question is particularly likely to inflame passions in areas that Kurdish leaders have said they want to incorporate into the federal Kurdistan region in northern Iraq. Along with Kurds, these areas are home to a diverse population of Arabs, Turkmens, and smaller minorities, all of which have been engaged in a tense standoff over Kurdish aspirations, which they resist almost unanimously. The situation holds the potential for violent conflict. Several incidents in these disputed areas over the past two years required U.S. commanders to establish joint military checkpoints along the so-called trigger line dividing Iraqi Army troops from Kurdish regional guards. Finding a negotiated solution to the tug of war over these areas, with the city of Kirkuk at their center, will be critical for Iraq's future.

All sides see the census's ethnicity question as a proto-referendum on these areas status. Everyone assumes that in a referendum Kurds would vote in favor of accession to the Kurdistan region while the vast majority of non-Kurds would vote against. If the population in a given area is found to be majority Kurdish, the political case for linking this area to the Kurdistan region will be greatly strengthened -- regardless of the wishes of the area's non-Kurdish population, whatever its size. The census, in other words, would increase the momentum toward a non-negotiated solution of these areas' status via an ethnically driven, zero-sum-game plebiscite. Going forward with the ethnicity question intact, then, would almost certainly lead to an Arab and Turkmen boycott, as well as popular protests in disputed territories, likely culminating in violence.

Even questions of language, obviously relevant for the provision of government services like education, should be dropped else the exercise create too many disputes for Iraq to survive.

There may be something to this argument. In Yugoslavia, the various republican and national censuses in the Communist era provided ample data for disputes over the direction of demographic changes and their import, helping to fuel various conflicts until, fittingly, the outbreak of war made the 1991 census a
partial one that excluded Kosovo and other parts of Yugoslavia on account of boycotts and conflict. I can't help but feel this parallel doesn't say good things about the survivability of Iraq, mind.

Saturday, October 23, 2010

On the necessity of immigrants




[. . .]





Friday, October 22, 2010

On Morocco's expulsion of sub-Saharan African migrants and its import

An article recently popped up,'s "Expulsion de centaines de Subsahariens vers la frontière algérienne" ("Expulsion of hundreds of sub-Saharan Africans towards the Algerian border"), commenting on a recent e3xpulsion of illegal migrants from Morocco.

In a statement, [Médicins Sans Frontières] said that between 600 and 700 people were arrested during police operations in several cities Royaumme between August 19 and September 10. Living in Al-Hoceima, Casablanca, Fes, Nador, Oujda, Rabat and Tangiers, these people were then deported to the border with Algeria. MSF also said that during several raids, police destroyed shelters of illegal immigrants with bulldozers. Left in this no man's land, some immigrants have managed to return to Oujda on foot, completely helpless.

MSF said it had taken care of 186 migrants including 103 who had injuries related to violent arrests. According to its chief of mission in Morocco, Jorge Martín, his team has seen "the direct consequences of the expulsions on the state of physical and mental health of migrants." In addition, MSF said it had seen a "dramatic increase" in cases of health problems related to violence.

The NGO called again for Morocco to meet its obligations under international law, Morocco is a signatory to the UN convention on the rights of migrant workers and their families. Similarly, it called on Morocco to "respect the dignity and integrity of migrants and avoid exposing them to a situation of greater vulnerability and insecurity" in its implementation of measures to control illegal migration.

The comments at this article are interesting, some commenters criticizing their country's treatment of these migrants, others (like this one, who wrote in English) blaming the migrants and their countries in terms not altogether different from those used to describe other groups of migrants from other poor countries.

If Medecins sans Frontieres wish to help, they should distribute CONTRCEPTIVES to those in Africa. The problem: Fertile Women and Men with nothing to do but make babies they can not take care of. Compounded by poverty, Illeteracy and Governments presided over by Dictators whose objectif is to get rich at the cost of the poverty of the populace.
I am very proud of Morocco and its achievements of the last 10 years. However it still has a lot to do to take care of its own people to provide decent housing, jobs, health systems and provide jobs for those who are still looking to be employed. Why then should Morocco has to add to its already HEAVY burden and spend Monies on these African migrants? This would be a waste of cash that can be used to eradicate shantytowns, open up decent schools, hospitals, old folks homes, and assist the Street Cildren as well as handicapped, divorcees, etc.

This raises an interesting question. Continued and intensifying European surveillance of its Mediterranean frontiers makes it increasingly difficult for migrants to make it in substantial number to their preferred destinations. Despite this, basic subsistence needs continue to push migrants north from Sub-Saharan Africa, towards North Africa. North African countries, incidentally, including Morocco, are substantially richer than their southern counterparts, at least as measured by measures such as HDI and GDP per capita. More, many of these countries have close ties with at least some Sub-Saharan African countries--the Maghreb and most of the Sahel and all of Senegal were part of the French Empire, and share a common language and religion. If migrants move north to Morocco (and its neighbours) and find themselves stuck there, doesn't that imply that Morocco (and its neighbours) will soon find themselves with large immigrant communities of their own?

Thursday, October 21, 2010

The latest news from Tunisia






Wednesday, October 20, 2010

Philip Longman on global aging

Over at Foreign Policy, demographer Philip Longman presents a basic overview for that magazine's readers about aging: its scope, its presence in the Third World, its heavy impact in Asia, and so on. Readers of this blog might be interested in his summary. Me, I was interested in his essay's conclusion.





The wholesale shift towards family enterprises that Longman predicts doesn't strike me as a likely solution to subreplacement fertility. The emergence of cultural norms and economic and political institutions which allow people to form families of various kinds without penalties or stigma, perhaps with the addition of new reproductive technologies to facilitate reproduction for longer periods of time and despite various problems, is the way to go. What do you think?

Tuesday, October 05, 2010

Technology and reproduction, now and in the future

This year's Nobel Prize in Physiology or Medicine went to Robert G. Edwards, the British scientist who developed the technology of in-vitro fertilization

Today nearly four million people have been born thanks to in vitro fertilization, which occurs when sperm is injected into an egg cell outside the body and the resulting embryo is implanted back into the womb. (Watch a video of how in vitro fertilization works.)

Edwards first envisioned IVF during the 1950s and went on to develop and hone the technique in the 1960s and '70s.

He achieved his first success on July 25, 1978, when Louise Edwards, the world's first "test-tube baby" was born in the United Kingdom. Louise is unrelated to the scientist.

"This is a wonderful achievement and a great testimony to Edwards's pioneering work in reproductive science," said Richard Kennedy, a fertility expert at University Hospital in Coventry, U.K., and secretary general of the International Federation of Fertility Societies.

"The development of IVF has enabled many millions of couples to have a child who might not otherwise have been able to," he said in a telephone interview.

[. . .]

More than 10 percent of couples worldwide are infertile. In the past medical help was limited, but today IVF therapy results in successful births for roughly one in five of every fertilized egg implanted.

The odds for a healthy couple conceiving naturally are about the same.

Reproductive medicine allows for the possibility of very significant changes on patterns of childbearing. Given the increasing tendency of people to postpone childbearing to later and later ages, for economic and other reasons, demand for the technology based on that factor alone (in societies well advanced in the demographic transition) is set to grow. Québec, for instance, has opted to pay for the first three rounds of IVF treatment. One clinic in Toronto--almost certainly not alone in the world--is promoting the idea that women who anticipate postponing parenthood until later in life should take care to have some of the ovas collected and frozen, for later fertilization and implementation. Other, more outré examples, from now and in the foreseeable future, can probably be imagined by my readers.

Anna Smajdor's article "State-funded IVF will make us rich… or will it?" makes the good point that expecting IVF to rejuvenate economies by producing more potential workers--justifying state expenditure on IVF--is, at best, a profoundly problematic idea, one that doesn't take into consideration the various economic, emotional, health, and other costs of reproductive technology. IVF, and other like treatments, developed in order to meet the needs of couples who wanted to have children at a time of their choosing. The effects of these many individual desires on demographic processes in the long run are doubtless many, but one prediction I do feel safe in making is that the timespan of a human generation will become significantly longer: between the existing postponement of births and the ability to facilitate births later in life, age-specific fertility in older cohorts can be expected to rise significantly at the expense of the younger ones.