This blog is intended to go along with Population: An Introduction to Concepts and Issues, by John R. Weeks, published by Cengage Learning. The latest edition is the 13th (it will be out in January 2020), but this blog is meant to complement any edition of the book by showing the way in which demographic issues are regularly in the news.

You can download an iPhone app for the 13th edition from the App Store (search for Weeks Population).

If you are a user of my textbook and would like to suggest a blog post idea, please email me at:

Wednesday, October 31, 2012

Populations at Risk From Hurricane Sandy

Hurricane Sandy hit New York and New Jersey head-on with devastating effect, thus far killing 62 people in the US, according to the latest news that I could find at this moment. Here in the US, the news is about the US almost exclusively, but the hurricane left devastation in far less resilient places in the Caribbean, especially Haiti, before it roared up the east coast of the US, as the BBC News points out:
Fears are growing of food shortages in Haiti, after the strong winds and heavy rain of Hurricane Sandy caused extensive crop damage.
Aid workers and officials are also warning that flooding could lead to a sharp rise in cholera cases.
Sandy is blamed for some 70 deaths in the Caribbean. Of these more than 50 were in Haiti.
The cleanup everywhere will be slow, tedious, and costly, but as almost always, it will be the poor who will suffer the most and for the longest.

Tuesday, October 30, 2012

The Decline in Violence--Things That Don't Kill Us As Much Any More

If there is one thing that we are likely to associate in our minds with civilization it is the control of violence. Harvard psychologist Steven Pinker has written about this in his recently published book The Better Angels of Our Nature: Why Violence Has Declined. This week's Economist has picked up the threads of the book, which are as follows:
The path is from non-state societies (homicide rates around 100 per 100,000) to medieval proto-state societies (tens per 100,000) to early modern society (high-single digits per 100,000) to peaceful modern Europe (around 1 per 100,000), roughly an order-of-magnitude drop each time.
In other words, as people increasingly trust the government to control violence, they are less prone to take it into their own hands. On the other hand, in the United States there are some clear regional differences in the extent to which people trust the government.
Murder rates are about four times higher in America than in western Europe. And guns are not the only reason; murder by stabbing and clubbing is higher, too. The murder rate is higher among blacks, but American whites are more violent than European whites. The South is America's most violent region; both blacks and whites in the South are more violent than those in the northeast. In other words, the murder rate is highest in those states that most disdain the sovereign ("government") and champion self-reliance.
Note, however, that the South tends to have higher death rates from several other causes of disease besides violence, so we always have to be careful of that correlation versus causation thing.

Sunday, October 28, 2012

Urbanization is Not Necessarily a Driver of Wealth

Cities have historically been the places where wealth is most likely to be created. That is still true, but it is less true in cities of developing countries than in the richer countries, depending especially upon the geographic region under discussion. The latest World Development Report (2013) from the World Bank focuses on jobs, and in that report there is a comparison of gross domestic product and percent urban over time in richer and poorer countries. The comparison is disheartening, as the Atlantic Wire notes:
Urbanization usually leads to higher GDP because of higher levels of productivity, the report says, which is illustrated in the graph to the left [see the article]. All five of the East Asia and Pacific countries in the graph show a steady increase in GDP per capita as people move to cities. But that did not happen for Sub-Saharan Africa; the graph on the right shows a sporadic relationship between urbanization and GDP. Part of the reason may be because much of non-farm work in Africa is from microenterprises and household businesses that do not earn much. "These businesses make a significant contribution to gross job creation and destruction," the report says, "although not necessarily to net job creation and productivity growth."
With population growth rates being higher in Sub-Saharan Africa than anywhere else in the world, these are issues of global concern. Indeed, the front page of the World Bank website features a blog post by Wolfgang Fengler talking about the struggle in Africa to bring its life expectancy up, and a more hopeful story suggesting that Africa could feed itself if the sub-continent were to implement a variety of policy changes outlined by the Bank.

Friday, October 26, 2012

Science Trumps Superstition in the Year of the Fiery Horse

Thanks to Shoshana Grossbard for the link to a recently published paper exploring what really happens to girls born in the Year of "Hinoeuma" (the Year of the Fiery Horse, aka the Fire Horse). You will recall that in the Chinese zodiac calendar used in Japan, the Year of the Fiery Horse occurs every 60 years and it is believed that girls (but not boys) born in that year will have troublesome characters and so will be hard to marry off. Indeed the birth rate dropped dramatically in the last such year--1966--but of course there were some girls who were born that year nonetheless. Hiroyuki Yamada of Osaka University has gone back to see what happened to those women, compared to women in surrounding cohorts, and compared to men. 
We find that there is no evidence of disadvantages to fire horse women in human capital investment, performance in the marriage market, or intra- household allocation of resources after marriage.
One of the important changes that has occurred since these women were born in 1966 is that arranged marriages have been almost entirely overtaken by love marriages. Older parents arranging a marriage may worry about the year in which a girl is born, but her same or similar age lover seems not to care. Furthermore, since there were fewer women born in that year than in the surrounding years, they seemed to have done a bit better in the marriage market than you would otherwise have expected. Another blow to superstition.

Thursday, October 25, 2012

Will Waitress Moms Move the Election?

The US presidential election is getting ever closer to election day (although I've already voted, so I guess my personal election day is behind me), and the two candidates are essentially tied in the national public opinion polls. This means that everyone is looking for that group of undecided voters who, if they actually do go to the polls, will make the difference one way or another. This week's favorite demographic group is "waitress moms," as the NY Times explains:
Whether or not the term “waitress moms” endures, it defines a distinct demographic: blue-collar white women who did not attend college. And they are getting a lot of attention from both campaigns as the presidential race barrels toward its conclusion because even at this late date, pollsters say, many waitress moms have not settled on a candidate. They feel no loyalty to one party or the other, though they tend to side with Republicans.
“Blue-collar women are most likely to be the remaining movable part of the electorate, which is precisely why both campaigns are going at them as hard as they are,” said Geoff Garin, a Democratic pollster, who is advising Priorities USA, a pro-Obama “super PAC.”
About 9 percent of all voters in 2008 were white women without college degrees who had an annual household income of less than $50,000, according to exit polls.
Note that there is a bit of demographic fudging here when calling these women "waitress moms." Most are not waitresses and many are not moms. But who's going to check on that? Maybe the "soccer moms" of the 1996 election, who may or may not have had anything to do with the outcome of that election.

Wednesday, October 24, 2012

Should You Invest in Africa?

The World Bank appears to be bullish on Africa, according to this week's Economist, although I admit that I have not found the World Bank report that is obliquely referenced in the Economist article. Still, the Economist gives some details, and two of the four reasons for this positive attitude are related to demographics:
First, the continent has the right kind of population growth: most Africans live increasingly longer while having fewer children, rather than the other way round. The UN says that Nigeria may overtake the United States by 2055 as the third-most-populous country after India and China, yet simultaneously reduce its birth rate.
Second, rapid urbanisation is creating efficiency gains and luring investors to capital cities that have begun to thrive and where growing population density cuts transport times and fosters small-scale industrialisation.
The other two reasons for optimism are the opportunities for technology to make inroads, because most things are at such a low level, and the improvement in governance in the region.

At the same time, this sense of Africa as a place to invest money with expectation of a substantial return seems at odds with the email announcement I received today from Worldwatch seeking donations to help them bring sustainable sources of energy to Africa "where seven out of ten people lack reliable and affordable access to electricity."

Tuesday, October 23, 2012

Mexico's New Migration Law

Mexico is largely a migration-sending nation, so it has not historically worried too much about immigration policy. If you want to become a Mexican citizen, for example, you can apply for a visa to move there (which may or may not be approved, depending upon you and your circumstances) and after five years of legal residence you can apply for citizenship. But Mexico has been facing a politically more sensitive issue--that of migrants from Central America passing through Mexico on the way to the US. And, of course, some of them wind of staying in Mexico. To cope with these circumstances, the Mexican Parliament recently passed a new Migration Law, as detailed in a new report from the Migration Policy Institute by Mexican scholars Francisco Alba and Manuel Angel Castillo. 
The law aims to develop a migration policy that respects the human rights of migrants, is comprehensive in its coverage, facilitates the international movement of people, meets the country’s labor needs, ensures equality between Mexican natives and immigrants to Mexico, recognizes the acquired rights of long-term immigrants, promotes family unity and sociocultural integration, and facilitates the return and reintegration of Mexican emigrants. 
As the authors note, it is too early to tell whether the law will really be implemented and enforced in any meaningful way, but this is an important step for Mexico, which has not passed any migration legislation of note since the 1974 General Law of Population. 

Monday, October 22, 2012

Send in the Migrants?

Immigration policy in the United State is focused almost exclusively (and unsuccessfully) on keeping out undocumented immigrants. In Britain, the government of David Cameron seems to have focused on limiting the number of skilled legal workers. The Economist is opposed to this, as they discuss in some detail in this week's edition. 
In the past two years the coalition government has clamped down hard on legal immigration. David Cameron, the prime minister, has stuck with a promise to cut net migration to the “tens of thousands” by the end of this parliament in 2015. In practice this means curbing immigration from outside the European Union. Foreign students, who used to have the automatic right to work for two years after completing their courses, will have only a few months to find a licensed sponsor who will pay them at least £20,000 ($32,300) a year. The changes seem to be having the desired effect. In the year to June the number of work-related visas issued fell by 7%, while 21% fewer study visas were handed out (see chart).
As is true in the US, the problem is complicated by the fact that the economy is demanding more technical and scientific skills than the British schools are producing among the British-born. So, at the same time that there is unemployment among the British, there are jobs that need to be filled by immigrants because they are the ones with the requisite skills. This is a problem that goes beyond migration policy. It speaks to educational policy, and probably also to labor policy, since it is almost certainly the case that skilled immigrants are being paid less than home-grown talent. This is another aspect of globalization, but instead of job outsourcing, it is job insourcing (if that's a word). You know what I mean.

Saturday, October 20, 2012

Malthus in Manhattan

Well, OK, it's technically not Manhattan, but it is New York City generally where Mayor Michael Bloomberg is pushing a plan to develop publicly subsidized new super-small apartments (“microunits”) as part of his goal to provide 165,000 homes for poor and moderate-income families across New York City by 2014. However, as the New York Times reports, there is a particular demographic group that is complaining about this strategy--large poor families:
This group includes members as disparate as West Africans in the South Bronx, Hasidic Jews in Brooklyn and Bangladeshi in Queens, who are united by their inability to afford the high prices for large market-rate rentals and their inability to find publicly subsidized alternatives even as the overall housing stock has swelled.

So Mahamadou Tounkara and his wife and six children squeeze into one room of a market-rate, three-bedroom apartment in the South Bronx that they share with two other families because they cannot afford the monthly $1,112 rent alone. Twenty more large families at their mosque are in a similar bind even as several new city-financed buildings have risen nearby.
 “It’s hard to live like this,” said Mr. Tounkara, who is a part-time auto mechanic. “You want more space, but if you don’t have money, how are you going to pay for it?”
Mr. Tounkara, the father of six, who does not have a high school diploma, said he moved to the Bronx in 1996 for a better life than he had in his native Mali. His wife, Assetou, followed four years later, and they had six children. “I like kids, so I make more,” he said. “My culture has a lot of kids.”
Now, here is the question that anyone would reasonably ask: If you are a large poor family, why are you living in the most expensive city in the United States?
“It’s not the city’s job to give open-ended subsidies and reward people for having more members in the family,” said Nicole Gelinas, a senior fellow at the Manhattan Institute for Policy Research. “It is responsible behavior not to have children until you can reasonably support them.”
Malthus, who strongly made the case that people shouldn't have children until they can afford them, would strongly approve of that attitude.

Friday, October 19, 2012

Humans Help to Spread Malaria

Malaria requires two things--a host (a human) and a vector (the mosquito). In areas where malaria is endemic (i.e., a high fraction of people have the parasite in their body), the emphasis has been on controlling mosquitos and exposure to mosquitos. But it has also been known for a long time that malaria-positive humans can spread the disease by going to places where mosquitos exist, being bitten, and then having the mosquito infect someone else who would not otherwise have been at risk. A new study published in Science by a well-know group of malaria researchers shows how this phenomenon can now be tracked and mapped using cell phone data. NPR summarizes the research:
Researchers at Harvard School of Public Health tracked the texts and calls from nearly 15 million cellphones in Kenya for an entire year and then used the data to make a map for how malaria spreads around the Texas-sized country. The results were unexpected.
The roads to and from the capital city, Nairobi, are the most heavily traveled, yet they aren't the most important for spreading the disease throughout the country.
Instead, regional routes around Lake Victoria serve as the major disease corridors for the parasite. And, towns along the routes are hot spots for transmitting malaria to the rest of the country.
 The data also confirm what a few epidemiologists had feared: Malaria seems to be getting into some African megacities, like Nairobi.
Malaria doesn't typically occur in large cities because mosquitoes don't thrive there. "But some studies suggest that mosquitoes are adapting to the city," Douglas Fuller, a geographer at the University of Miami, tells Shots. "This study shows you where Nairobi is getting its malaria."
To curb malaria throughout Kenya, the disease-travel map points out precise areas for concentrating malaria control efforts and suggests places where stopping malaria won't have a big impact.
The idea would be that, because of the heavy penetration of cell phone usage in developing countries, automatic messages could be sent to be people along specific high-risk routes reminding them to take precautions against mosquitos (sprays, bed nets, etc.). Every little bit helps.

Wednesday, October 17, 2012

World Food Day 2012

It seems that on almost every day of the year we commemorate something of importance to demography and the 16th of October is the traditional World Food Day, celebrating the creation by the UN of the Food and Agriculture Organization, as I have noted before. Full disclosure: I have been a consultant to the FAO and one of my former PhD students used to work there, and my involvement recognizes my belief in the important role they play in trying to ensure that we are all fed as well as possible.

There is a general belief that we actually grow enough food on this planet to feed our 7 billion people, if only we didn't waste quite a bit of it, and if only we made sure that food surpluses in some areas were transported to food deficient areas. But the reality of the world is that food will always be wasted, and distribution systems will always be imperfect. Thus, we genuinely need to grow more food than would technically be necessary to feed 7 billion in order to adequately feed 7 billion. At the moment, we don't do that. Since we don't do that, will we be able to feed the 10 billion that the UN projects to be around in 2057? We don't know the answer to that question, but the FAO is working on it...

Tuesday, October 16, 2012

Immigration and the Presidential Debate

Tonight's presidential debate between President Obama and Governor Romney featured some audience-initiated questions about US immigration policy. I was happy to see this, although I gave both candidates low grades on their responses. Why? Because neither one is willing to confront the elephant in the room when it comes to immigration reform--family reunification. Romney talked about how he wants people to come in the "front" door (legal immigrants), rather than the back door (undocumented immigrants), without referencing the fact that the front door is clogged with close relatives of legal immigrants who, when they enter the country, have a low probability of contributing to the economic needs of the nation, whereas those coming in the back door are coming precisely because there are jobs that no one else wants. President Obama noted his hard line on the border without referencing the fact that the economy, more than border enforcement, has shortened the line of people trying to cross the border without documents.

All of these things were in play in my mind because earlier this morning my mother-in-law died (peacefully, at age 93). Her father had migrated from Denmark to Iowa late in the 19th century, without any expectation that any of his Danish family members would join him in the US (and none did). He arrived in Iowa, married a child of immigrants (also from Denmark) and they moved to South Dakota, where my mother-in-law grew up on a farm. The opportunity to work brought these people, legally, to the US and that is exactly where our national immigration policy needs to be today---but it isn't. And I find that frustrating.

Monday, October 15, 2012

Jersey Boys (and Girls) Have Lowest Divorce Rate in US

Yesterday's New York Times was all over a recent data from the recently released American Community Survey 2011 showing that the "divorce rate" is lower in New Jersey than in any other state. Who would have guessed? Well, actually, anyone who has been observing the data over time would have seen that divorces per person have been low in New Jersey for some time. In general, they are lowest in the northeast and highest in the south. An important reason for that is that you have to get married in the first place in order to get a divorce and marriage rates are lower in the northeastern states than most elsewhere in the country. I put "divorce rate" in quotations to remind you that when the Census Bureau calculates its divorce rate, the denominator is simply the number of people aged 15 and older. However, a true divorce requires that the denominator be the number of married people--the people actually at risk of getting a divorce. The fewer people married (as in New Jersey), the lower the divorce rate will automatically be. Those marriage data are harder to come by than they used to be, however. The Census Bureau notes that:
Historically, data on marriages and divorces in the United States were collected from marriage and divorce certificates filed and collected at the state-level through the National Center for Health Statistics (NCHS) vital statistics system. In 1996, the Centers for Disease Control and Prevention (CDC) and the NCHS discontinued the collection of detailed state-level vital records data from marriage and divorce certificates. Beginning in 2008, questions about marital events were added to the ACS to collect national and state-level marriage and divorce data. These new marital events items fill a void in the marriage and divorce data collected in the United States.
I will say that the New York Times did a good job of rounding up a star-studded cast of American sociologists to comment on these results and the statistical issues were at least alluded to, if not exactly made specific in the article.

Saturday, October 13, 2012

Keep Your Eye on the Older Population

For virtually all of human history the real focus of societies has been on the younger population. The dramatic declines in mortality over the past several decades have, of course, accelerated the increase in the number of older people, while the drop in the birth rate has steadily increased their share in the total population. Such was the reminder this week from the United Nations Population Fund (UNFPA) as it celebrated "The International Day of Older Persons." BBC News reported on the event:
"Today we have one in nine persons aged 60 or over," says the UNFPA's Dr Ann Pawliczko, "but by 2050 it'll be one in five, and by that time there will be more older persons than those under 15 years."
The UN sees these statistics as a cause both for celebration because more people are living longer, and some concern because the change presents an economic and social challenge.
Dr Pawliczko would like see more countries prepare for the coming demographic shift. After all, she says, there is no doubt it is happening.
"We can be very certain about the numbers for 2050 because persons who will be aged 60 in 2050 are already born. This not speculation."
But there is still considerable speculation about what will happen to the birth rate, in both developed and developing nations.
"Historically, fertility has been falling across Europe," says Professor Jane Falkingham, director of the ESRC Centre for Population Change at Southampton University. "But actually if we look at the most recent period, the last 10 years or so, we see rises in fertility in the most advanced countries."
Evolutionary biologists might not be surprised by this. The idea that as we get richer we have fewer children is, from their perspective, very odd. Normally natural selection produces individuals who are good at converting their resources into lots of fertile descendants.
It's a demographic paradox that in the past few centuries, developing societies haven't been filled by families who raise as many kids as they can possibly afford.
Of course, this may not make a huge difference to world totals, since the populations of the developing nations far outnumber those of the richer nations. Still, it is sobering to think that even with the current UN projections from their Population Division, we may hit 10 billion people by 2057--less than a half century from now.

Friday, October 12, 2012

What's the Next Scary Cause of Death?

I conclude Chapter 6 on the Health and Mortality Transition with the reminder, written in 1935, from Hans Zinnser (an American-born son of German immigrants, and a Professor at Harvard) that diseases are always lurking in the shadows. This week's Economist reviews two new books speaking to that very issue: (1) "Contagion: How Commerce Has Spread Disease," by Mark Harrison (Yale University Press, to be published in America in January 2013); and (2) "Spillover: Animal Infections and the Next Human Pandemic," by David Quammen (W.W. Norton). While the books almost certainly are good and useful, the introduction to the story is itself pretty scary:
ON OCTOBER 2nd a British traveller, flying home to Glasgow from Afghanistan, began to feel ill. Within hours he was diagnosed with Crimean-Congo Haemorrhagic Fever, a virus nasty enough for him to be put onto a military transport aircraft for transfer to an isolation hospital in London. Less than 24 hours later he was dead.
This outbreak, on top of another death last month in Saudi Arabia from a previously unknown virus, a cousin of the Severe Acute Respiratory Syndrome (SARS), has set global health agencies on edge. Ten years ago the deaths of a couple of travellers from foreign parts might not have been news at all. But the fright of the SARS outbreak in 2003 has left a lasting impression, and scientists and public-health officials now tend to see any putative disease threat through its lens.
These threats are, of course, layered on top of the deaths from meningitis that have been occurring over the past few weeks from patients receiving contaminated steroid shots. These are all reminders that despite our increasing life expectancy, we can never afford to let our guard down.

Thursday, October 11, 2012

The Day of the Girl Child

The US Agency for International Development (USAID) designated today as the "International Day of the Girl Child." The planning for this event was clearly already in the works when the fourteen-old girl was shot in the head by the Taliban in Swat Valley of Pakistan for publicly supporting education for girls.
Malala Yousafzai, in critical condition two days after being attacked in the north-western Swat Valley, arrived by helicopter in Rawalpindi from Peshawar.
The Taliban, who accuse the young activist of "promoting secularism", have said they will target her again.
Using the pen-name Gul Makai, she wrote about suffering caused by militants who had taken control of the Swat Valley in 2007 and ordered girls' schools to close.
The Taliban were ousted from Swat in 2009, but her family said they had regularly received death threats.
They believed she would be safe among her own community, but on Tuesday, she was stopped as she returned home from school in Mingora, in north-western Swat, and shot in the head.
I was thinking about these issues this evening as I watched the Vice-Presidential debate, which featured near the end the views on abortion of two Catholic males. One (Paul Ryan) has publicly supported the idea contained within the Republican Party platform that would define personhood as beginning at the moment of conception, which is interpreted to mean that even young girls who are raped should not be allowed to have an abortion. He changed his position a bit tonight, but he is clearly opposed to abortion for all American women. The other (Joe Biden) publicly stated his personal opposition to abortion, while also believing that women need to make their own reproductive decisions for themselves. Which of those views seems more like the Taliban approach?

Wednesday, October 10, 2012

How Bad are Cities for Your Mental Health?

Until a few decades ago, cities were harder on your physical health than were rural areas. The advent of modern public health and medical technology has essentially turned that around, so that life expectancy is almost uniformly higher in urban areas of developing countries than in rural areas. But what about mental health? As long ago as 1938 Louis Wirth was arguing that the high density and impersonal nature of cities was not good for human existence. Then came Calhoun's famous studies of the rats of NIMH, showing how disruptive high density living can be in the rat kingdom. In an article in this week's Nature, Alison Abbott raises this issue again, but this time looking at specific mental illnesses to see if they might have distinctive urban origins in the way the brain works in different urban environments.
Now, a few scientists are tackling the question head on, using functional brain imaging and digital monitoring to see how people living in cities and rural areas differ in the way that their brains process stressful situations. “Yes, city-stress is a big, messy concept, but I believed it should be possible to at least see if brains of city-dwellers looked somehow different,” says Andreas Meyer-Lindenberg, director of the Central Institute for Mental Health in Mannheim, Germany. And if scientists can work out what aspects of the city are the most stressful, the findings might even help to improve the design of urban areas. “Everyone wants the city to be beautiful but no-one knows what that means,” says Meyer-Lindenberg. Wider streets? Taller buildings? More trees? “Architects theorize a lot, but this type of project could deliver a scientific basis for a city code.”
You can see that this goes beyond the earlier arguments of density being a problem. Here the focus is on the built environment, more than the social world of urban places. New technologies in geographically tracking the activity spaces of people have also allowed people to think in new ways about what we might be able to learn about the brain-environment relationship.
Meyer-Lindenberg is planning an even more technologically ambitious project with geoscientists at the nearby University of Heidelberg, who have generated a high-resolution map of their city, and physicists at the Karlsruhe Institute of Technology in Germany, who have developed a mobile device that allows people to be tracked and tested for a week as they walk and work around Heidelberg. The device can recognize when participants reach a specific location — such as a green space or a particularly noisy intersection — and instantly question them about their state of mind or send them a cognitive test to be completed on the spot. The scientists will then ask the participants to come into the lab for brain-imaging studies that examine how they process stress and emotion. By correlating the imaging data with their states of mind at different locations, the team hopes to trace how different aspects of city life affect the brain — whether, for example, strolling through a park really does have a calming influence on the amygdala and cingulate cortex.
At first blush, these seem like rich city issues, as I have noted before, but one could hope that if this research revealed that specific types of urban environments really were beneficial or detrimental to health, then there would be motivation to do something about them in cities of developing countries as well--those places that will absorb most of the increase in human numbers over the next few decades.

Monday, October 8, 2012

Celebrating the Day of the Dead--No, No, Columbus Day

Today is a federal holiday in the United States dedicated to the memory of Christopher Columbus, an Italian sailing for a Spanish government which was one of the most religiously repressive regimes of all time. They killed or banished those who disagreed with them, and Columbus's arrival in the Americas wound up leading to the deaths of millions of the indigenous people in the New World, even if his intent was "only" to enslave them. Remind me again why we celebrate this?

Sunday, October 7, 2012

Your House May be Killing You

For millennia, humans have protected themselves from the environment by building homes of some kind or another. Housing protects you, right? Nicholas Kristof of the New York Times suggests that homes may now be potential killers because the materials that go into the construction of modern homes contain various amounts of formaldehyde that may send out fumes that we breath. Why is this important? Because those fumes are carcinogenic.
The chemical industry is working frantically to suppress that scientific consensus — because it fears “public confusion.” Big Chem apparently worries that you might be confused if you learned that formaldehyde caused cancer of the nose and throat, and perhaps leukemia as well.
The industry’s strategy is to lobby Congress to cut off money for the Report on Carcinogens, a 500-page consensus document published every two years by the National Institutes of Health, containing the best information about what agents cause cancer. If that sounds like shooting the messenger, well, it is.
The chemical industry was outraged, because it sells lots of formaldehyde that ends up in people’s homes, often without their knowledge.
 “Nearly all homes had formaldehyde concentrations that exceeded guidelines for cancer and chronic irritation,” according to a 2009 survey by the California Energy Commission.
Kristoff notes that we have had two previous major bouts of denial on the part of manufacturers of carcinogens--asbestos and tobacco. Eventually public opinion caught up with science on both of those because everyone's good health (except maybe that of the producers of carcinogens) is at stake.

Saturday, October 6, 2012

Coping with Population Aging

The aging of the US population has been front-and-center in the presidential race, with discussions about how to fund (or not fund) Social Security, Medicare, and Medicaid. A new volume from the National Academy of Sciences has just been inserted into the discussion, and one can hope that policy makers will pay attention (which is naturally one of the reasons why the National Academy of Sciences was created in the 19th century, although it is not directly funded by the US Government). The book is called "Aging and the Macroeconomy: Long-Term Implications of an Older Population." Not a very sexy title, but it is does describe the study's purpose. The committee put together to do this volume, under the auspices of the Committee on Population, was headed up by economic demographer Ronald Lee at UC, Berkeley, one of the world leaders in the economics of aging, and the introduction does a very nice job of laying out the policy alternatives:
There are four basic approaches for adapting to the new economic landscape created by an aging population, and for providing the resources to support the consumption of households in their later years: 
• Workers save more (and consume less) in order to prepare better for their retirements.

• Workers pay higher taxes (and thus consume less) in order to finance benefits for older people.

• Benefits (and thus consumption) for older people are reduced so as to bring them in line with current tax and saving rates.

• People work longer and retire later, raising their earnings and national output.

The fundamental issue that society faces is how to adapt in some or all of these ways to absorb the costs of population aging. Each option has different implications for which generation(s) will bear the costs, or receive the benefits, of an aging population.
The rest of the book lays out the details of those several options, and I will return to these themes over time, since they apply not just to the US, but to any and all societies experiencing these later stages of the age transition.

Friday, October 5, 2012

Can the Rich Economies Continue to Grow?

Everyone alive today has grown up in an era of economic growth and increasing productivity per work, which translates into higher standards of living. It has been periodically interrupted, to be sure, but the long-term trend in our lives has been up. Can that continue? That's the question asked in a new National Bureau of Economic Research (NBER) report by Robert Gordon, Professor of Economics at Northwestern University, and discussed by Martin Wolf, a columnist for the Financial Times. Professor Gordon's answer is generally in the negative. Not surprisingly, there are important demographic threads to the story.
Prof Gordon argues, to my mind persuasively, that in its impact on the economy and society, the second industrial revolution [the "general purpose" revolution] was far more profound than the first or the third. Motor power replaced animal power, across the board, removing animal waste from the roads and revolutionising speed. Running water replaced the manual hauling of water and domestic waste. Oil and gas replaced the hauling of coal and wood. Electric lights replaced candles. Electric appliances revolutionised communications, entertainment and, above all, domestic labour. Society industrialised and urbanised. Life expectancy soared. Prof Gordon notes that “little known is the fact that the annual rate of improvement in life expectancy in the first half of the 20th century was three times as fast as in the last half.” The second industrial revolution transformed far more than productivity. The lives of Americans, Europeans and, later on, Japanese, were changed utterly.
Prof Gordon notes further obstacles to rising standards of living for ordinary Americans. These include: the reversal of the demographic dividend that came from the baby boomers and movement of women into the labour force; the levelling-off of educational attainment; and obstacles to the living standards of the bottom 99 per cent. These hurdles include globalisation, rising resource costs and high fiscal deficits and private debts. In brief, he expects the rise in the real disposable incomes of those outside the elite to slow to a crawl. Indeed, it appears to have already done so. Similar developments are occurring in other high-income countries.
As you might expect, this column has generated a lot of comments on the FT website, many of which point out the obvious fact that many people in the past have incorrectly predicted that we had "reached the end of history." Prediction is always difficult, especially about the future, as the old saw goes. But it is compelling that the graph of productivity looks amazingly like the graph of the growth of the human population. Of course, we know that correlation does not imply causation...

Thursday, October 4, 2012

Can the World Handle a Growing Middle Class in China?

It is frequently repeated that China is on course to grow old before it grows rich. The Chinese themselves are unlikely to share that sentiment and, with a new round of leaders coming into power soon, that is unlikely to be one of the national themes. Thomas Friedman was in China recently and he raises a very different equation--can the world afford the growing Chinese middle class?
“Success in the ‘American Dream,’ ” notes Peggy Liu, the founder of the Joint U.S.-China Collaboration on Clean Energy, or Juccce, “used to just mean a house, a family of four, and two cars, but now it’s escalated to conspicuous consumption as epitomized by Kim Kardashian. China simply cannot follow that path — or the planet will be stripped bare of natural resources to make all that the Chinese consumers want to consume.”
The Chinese are going to have to invent a new future, and they may be doing just that, according to Friedman.
So Juccce has been working with Chinese mayors and social networks, sustainability experts and Western advertising agencies to catalyze sustainable habits in the emergent consuming class by redefining personal prosperity — which so many more Chinese are gaining access to for the first time — as “more access to better products and services, not necessarily by owning them, but also by sharing — so everyone gets a piece of a better pie.”
That means, among other things, better public transportation, better public spaces and better housing that encourages dense vertical buildings, which are more energy efficient and make shared services easier to deliver, and more e-learning and e-commerce opportunities that reduce commuting. Emphasizing access versus ownership isn’t just more sustainable, it helps ease friction from the differences between rich and poor. Indeed, Juccce translates Chinese Dream as “Harmonious and Happy Dream” in Mandarin. (“Green” doesn’t sell in China.)
This kind of Chinese "exceptionalism" would be a welcome feature of the future.

Wednesday, October 3, 2012

Reproductive Health in Accra, Ghana

I have mentioned before the research that I and my colleagues and graduate students have been doing for the past several years in Accra, Ghana. Although the overall scope of research focuses on spatial inequalities in health, funded largely by grants from the National Institutes of Health, an important component has been reproductive health, which is funded partly by a grant from the PRB and the Hewlett Foundation, and that portion of the research has been headed up by Allan Hill of Harvard School of Public Health and, more recently, the University of Southampton. The PRB has just posted to its website a 15-minute interview with Dr. Hill that describes some of the major findings. For an overview of the entire project, you can sit through a longer talk that I gave on campus here at SDSU last year. Enjoy!

Tuesday, October 2, 2012

Correlation Does Not Imply Causation

Our modern understanding of the world depends upon science, an essential part of the Enlightenment. An important part of science is organizing information into something meaningful, and this is the role of statistics. A key statistical concept that underlies virtually all of modern analysis is correlation. We use it all the time--we wouldn't know what we know without it. But we are also routinely admonished not to equate correlation with causation. Two things can be correlated without one causing the other. Does that matter? Daniel Engber of Slate discusses this issue very intelligently and with some new historical information generated from Google books that I, for one, find fascinating.
Those first, modest peaks of "correlation is not causation" show up in print in the 1890s—a date that happens to coincide with the discovery of correlation itself. That's when the British statistician Karl Pearson introduced a powerful idea in math: that a relationship between two variables could be characterized according to its strength and expressed in numbers. Francis Galton had futzed around with correlations some years before, and a French naval officer named Auguste Bravais sketched out some relevant equations. But it was Pearson who gave the correlation its modern form and mathematics. He defined its role in science.
And he digs up a great quote from more than 100 years ago:
The father of correlation did worry about its overuse, says Theodore Porter, a historian of science at UCLA and a Pearson specialist. A footnote to the second edition of The Grammar of Science, published in 1900, lays out a critique of spurious relationships in terms that would not look out of place on an Internet message board:
All causation as we have defined it is correlation, but the converse is not necessarily true, i.e. where we find correlation we cannot always predict causation. In a mixed African population of Kaffirs and Europeans, the former may be more subject to smallpox, yet it would be useless to assert darkness of skin (and not absence of vaccination) as a cause.
So it seems the fear of correlations was formalized—made into a turn of phrase, I mean—at around the time that correlations came into formal being. One might say (citing another correlation) that Pearson's work marks the transition from an age of causal links to one of mere relationships—from anecdotal science to applied statistics. As correlations split and multiplied, we needed to remind ourselves of what they meant and what they didn't.
The bottom line, though, is that correlations are important. You can't have causation without them, even if they don't imply causation on their own. But they do tell us that something is going on, and that we then need to figure out what that is. That's how science moves forward.

Monday, October 1, 2012

There Ain't No Such Thing as a Free Lunch

Most of the major news media covered the death yesterday of Barry Commoner at age 95. He was one of the early gurus of the global environmental movement, helping it to gain traction in the 1960s and 70s. He was a supporter of the First Earth Day in 1970 and that year Time magazine put him on its cover. At the same time, he was out of step with many people because, like so many Marxists, he did not accept the idea that population growth was very important when it came to the environment. Daniel Lewis, writing in the New York Times has a good summary of the story:
Dr. Commoner took aim at the “neo-Malthusians,” as he called those who, like the English scholar Thomas Malthus, foresaw perils in population growth. In a panel discussion with Dr. Ehrlich in 1970, he said it was “a cop-out of the worst kind” to say that “none of our pollution problems can be solved without getting at population first.”
He elaborated in his best-known book, “The Closing Circle,” published the next year. Reducing population, Dr. Commoner wrote, was “equivalent to attempting to save a leaking ship by lightening the load and forcing passengers overboard.”
“One is constrained to ask if there isn’t something radically wrong with the ship.”
This kind of resistance to seeing the whole picture of the world was uncommon for Commoner, whom everyone praised as an excellent scientist. So, despite his turning a blind eye to what, in my opinion, is the single biggest issue the world faces, Commoner's environmental legacy is nonetheless extremely important. He is perhaps best known for his four informal rules of ecology: (1) everything is connected to everything else; (2) everything must go somewhere; (3) nature knows best; and (4) my personal favorite, with just a bit of editing that others have provided--there ain't no such thing as a free lunch (TANSTFL).