Friday, November 28, 2008

How Green Was My McMansion


A recent story on NPR on a power company installing solar panels on its customers' homes and businesses was presumably intended as a glimpse of one utility's novel approach to cutting down on greenhouse gas emissions. The story began, however, with the most disturbing of anecdotes:
"When Sean Durkin built a 4,000-square-foot house in Charlotte, N.C., he wanted to install solar panels. But he gave up when he learned that it would cost about $40,000.

"We'd love to have the panels — if we could afford it — and be completely green," Durkin says. But given that his utility bill is only about $200 a month, he says "it made no sense."

Then he heard that his local electric company, Duke Energy, wants to install solar panels on hundreds of customers' roofs and vacant lots.

"If Duke could put them up and they're going to get a better deal with it, then at least I'm helping the cause, and that's what I wanted to do," Durkin says."

Yes, Sean Durkin apparently thinks he could be "helping the cause" if only he could afford solar panels on his 4000 square foot house. 4000 square feet!

Ok, clearly I could just end this post right there at the point where I snarfed out my coffee in disbelief upon hearing this tale of woe because what else do you need to know, right? There's been only about a majillion electrons spilled on the topic of green housing and grotesque overconsumption and general insanity that's been powering the US housing bubble. Nonetheless, I, as your intrepid blogger, will forge on because clearly Elizabeth Shogren, the reporter on this piece, and her editors at NPR did not feel the need to point out that if only Durkin had a teensy bit of sense, he'd be doing a hell of a lot more for The Cause if he'd built a reasonably sized home (and maybe would have had a bit of cash leftover to buy some solar panels himself.)

In fact, the US used to be a land of reasonably sized, though frankly still pretty darn large, homes. In 1970, the median new house in the US was 1385 sq feet, with a quarter of new homes still under 1200 sq feet in 1973. But by 2006, it was up to 2248, with 24 % over 3000 sq feet and only 4% under 1200. At the same time, the number of people per household, however, is dropping, down to 2.59 in 2000.

So, first of all, the per household consumption of energy for a 4000 sq foot house is 155.2 million BTU; for a home with between 1000-1500 sq feet, only 75.4, and for the range that the median new home falls in, 106.8. In other words, Durkin's house is consuming 45% more energy than the median new home and more than double that of a very reasonable living space of 1000-1500 sq feet. On top of that, a not-so-well insulated 1500 sq foot house is still better than a very well-insulated 3000 sq foot house. (And of course, an apartment in a multi-unit building is an even bigger winner: 60.2K BTU for a three+ bedroom apartment vs. 101.2K BTU for a three bedroom freestanding house.)

Sure, you say, but what crazy people could live as a family in a 1000 sq foot? Well, actually in Japan, the average home is about 1,020 sq feet, about the same as in Europe. Nonetheless, Europe, Japan, and the US all have roughly similar number of people per household, ranging from 2.1 to 3.1. In the US, though, even the median home size is a bloated 1795 sq feet.

And our gigundic houses correlate closely with our gigundic energy appetite, with the US per capita energy consumption, almost twice that of Japan and Germany. Our productivity doesn't quite make up for it either with US energy intensity (i.e. energy consumption per dollar of gross domestic product) exceeding theirs as well, 9113 BTU/$ for the US vs. 7021 for Germany, and 6539 for Japan.

When it comes down to it then, both Sean Durkin and NPR missed the point, stated quite nicely by Matthew Yglesias today:
"If you look at how people live in the United States, the real green individual is the poor person who lives in a small apartment, rides the bus to work, and consumes beef relatively sparingly. That guy’s environmental footprint is probably smaller in most ways than that of a prosperous person who goes out of his way to consume green products. [...] “to go green” on a social level would probably look very different from what an individual upper middle-class environmentally minded consumer’s personal efforts to do so look like."

Thursday, November 27, 2008

Something's fishy. And it's not what's for dinner.

(Warning: disorganized draft version...)
Reading Judith Rich Harris's The Nurture Assumption has left me highly skeptical of claims that parents have control over their teenagers' behavior. So, it's not a surprise that after reading the recent New York Times article "The Family Meal Is What Counts, TV On or Off", about how family meals are the amazing panacea for healthy eating habits and health-risk-related teen behaviors like drug use, smoking, and eating disorders, I was left thinking, "Really?"

The Times article is a report of the latest published study from Project EAT at the University of Minnesota, which continues to find correlations between eating family meals and pretty much anything happy and healthy you can think of. The study itself isn't available online unless you cough up $15, and my local library won't have it on microfiche until about 2040, so you have to draw all your conclusions from the Times report and the article abstract.

Based on survey data of students in Minnesota in the late 1990s, students eating healthier diets also ate meals as a family more frequently. It's not clear from the story or the abstract whether this means their overall diet or the foods they ate during family meals were healthier, but presumably the former. It's also not clear whether they took into account such obvious confounding variables as the ability of the kids' families to afford healthier food (which is nearly always more expensive than unhealthy food on a price per calorie basis) or the ability of the families to afford having an adult at home to prepare and participate in a family meal (not easy if you are working multiple jobs or second shift or have only one adult in your household in the first place.) Nonetheless, the Times story concludes that "the best strategy for improving a child's diet is simply putting food on the table and sitting down together to eat it."

The Times story claims that the implied causal relationship between frequent family meals and a healthier teen diet is supported by the fact that in a separate study 'family connectedness', a proxy for the psychological health of a family, was shown to be "less important than whether they regularly dined together" for the incidence of these teen health behaviors. (This article on connectedness did take into account socioeconomic status and race/ethnicity, which leads me to believe that the Journal of Nutrition Education and Behavior article did too; but there's no way to tell without reading the latter.) How the discovery that one independent variable A is more strongly associated with a set of dependent variables than another B can lead you to conclude that the A must then be a cause of the patterns seen in the dependent variables is beyond me.

Once you look at this second study, however, things rapidly become even murkier. The authors' definition of the variable 'family connectedness' is actually an averaging of the answers to the questions, "How much do you feel your mother/father cares about you?" and "Do you feel you can talk to your mother/father about your problems?" They say, as stated in the Times article, that the correlations they've found between family meals and adolescent health behaviors hold even if the effect of family connectedness on their models was controlled for.

The author of the Times article repeatedly stresses the importance of the connectedness factor in showing that its truly family meals that are the beneficial phenomenon in her blog. In fact, the connectedness questions actually look like they in part measuring how open your communication is with your parents, not how functional your home life is. I suspect that very hierarchical, authoritarian parenting styles are not going to give you high connectedness, but may very well still correlate with frequent family meals and even happy, healthy teens. A teeny piece of evidence towards this is that in the abstract of another Project EAT study, "Family meal patterns: Associations with sociodemographic characteristics and improved dietary intake among adolescents," Asian-American ethnicity correlated with higher frequency of family meals. The Asian-American student population in Minnesota in the late 90s was likely to be children of first or second generation immigrants--households where non-mainstream American family practices are likely to still be strong before the immigrants are fully assimilated into the local culture. These are probably the exact kids who are not happily sharing all the secrets of their teen years with their parents but who actually participate in a lot of family meals. It would be nice to see the two types of connectedness questions separated out---sharing secrets with your parents vs. feeling like your parents care about you. The latter seems like it would be a far better way to estimate how functional your family life is. In any case, the authors of the study also admit that "[r]egular family meals may also be a proxy in this study for other elements of family connectedness that are not captured in the measures used here."

More importantly for my point here, although their primary conclusion is that family meals may enhance the health and well-being of adolescents and that public education efforts should stress the benefits of family meals, they also say explicitly that "the study's cross-sectional design meant the results do not imply a causal relationship between eating family meals together adolescent health behaviors." (Emphasis all mine!)

So, why should we think that family meals are this magical ingredient that keeps our kids healthy and happy? I admit that I am a strong proponent in my own household for family meals. My husband could actually eat three meals at work a day, and has on occasion suggested that this would be easier for him and us as a family. This inevitably leads to me jumping up and down and throwing pronouncements like "Hell no, you're not going to start eating dinner at work!" around. Eating dinner together provides a reason for me to cook an interesting nutritious meal on a daily basis. It gives us a chance to all hang out without any major distractions for at least one short stretch. And, I just plain like family meals. But is it the cure-all for the social and public health problems of the day? Will our daughter grow up with a protective vaccine against the trials and tribulations of adolescence because of it?....um, I doubt it.

Why am I such a doubter? This is where the Harris theory comes in. Her idea in short is that---based on many, many behavioral genetic studies of adult personality, behavior, and intelligence---there is little to no effect on these same factors of growing up together in the same household. Nearly every study that purports to find some benefits of a particular parenting style or particular feature of home life does not control for the fact that parents and children share their genes. Without taking heredity into account, you just cannot sort out whether the effects you are seeing are caused by genes or environment. And, on top of that, based on how dissimilar identical twins raised together are---just as dissimilar as twins raised apart---growing up in the same household does not appear to have more than a weak effect on behaviors like substance abuse/use, depression, academic performance, and self-esteem.

So, in light of all of Harris' evidence, the so-called "surprising power of family meals" appears to be just another case of causation-correlation confusion in parenting practices. Healthy, happy parents are more likely to have healthy, happy kids because those kids share their parents' genes. Happy families do things like eat family meals together, care for each other, spend time together, and eat relatively healthy diets. The kids get good grades, don't run around raising hell with smoking, drinking, and drug-taking kids, and don't think about suicide. Living in a wealthier neighborhood with more highly educated, wealthier parents makes all this stuff easier and more likely, but not having a lot of money or education does not make it impossible.

The number of studies telling us that eating family meals together 'leads' to happy, healthy teens, and thus adults, may continue to increase, and strong correlation can hint at causation.
But without studies that rule out other possible causes, the case for causation here remains weak. (Frequent family meals and happy, healthy teens may very well strongly correlate with how often a family needs to get their car repaired, the number of letters following the parents' names, and their use for high SPF sunscreen, but no one would mistake any of those associations for the causes of healthy, happy teens!) It remains perfectly plausible that there is some independent cause or set of causes of both frequent family meal eating and high-levels of adolescent health and happiness!

So, if family meals aren't a cause, does it matter? Yes! If family meals are not an actual cause of better health and more happiness, then devoting scarce public health resources to promoting them may take resources away from finding and promoting actual sources of health and happiness. And for all we know increasing the frequency of family meals in unhappy families may make things worse for those families!

Please, someone, somewhere do a study that compares happy, functional families that eat together with happy, functional families that don't eat together to see if there's anything important to conclude. A nice test demographic that comes to mind is day students at English boarding schools. Some schools may require day students to have dinner at school, and others might not. Is there really an important difference? (My husband and his siblings spent their teen years at school until late in the evening, rarely if ever eating a family meal because of required evening study sessions and school dinner hour. They are all happy, healthy, successful members of society today. Not eating family meals together may have had effects on them, but not ones that resulted in them or all their schoolmates being unusually drug-addled, eating-disorder ridden, suicidal basketcases.)

Sunday, November 23, 2008

From the 'Interesting If It Were True' File


As a woman and a one-time computer scientist (at least I played one on TV!), I was immediately intrigued by Randall Stross's Digital Domain column headline last week, "What Has Driven Women Out of Computer Science?" In fact, the headline was completely inappropriate because Stross was actually asking why fewer women were entering the field than in the past, not why women already in the field were leaving. Sadly, things didn't improve much beyond the headline because it turns out that the premise of the article is Just Not True.

Stross's primary assertion is that, in contrast to computer science (CS) where the percentage of women receiving bachelor's degrees has been dropping, women "have achieved broad parity with men in almost every other technical pursuit. When all science and engineering fields are considered, the percentage of bachelor’s degree recipients who are women has improved to 51 percent in 2004-5 from 39 percent in 1984-85, according to National Science Foundation surveys."

In fact, closer inspection of the data shows that women are just as rare in many other technical fields. According to the National Science Foundation, in 2006, women made up 20.4% of bachelor's in CS, roughly similar to physics (20.6%) and engineering (19.5%) (including only 13.0% in electrical engineering!)

In addition, the 51% across "all science and engineering fields" is boosted by the fact the National Science Foundation statistics include behavioral and social sciences, like psychology, linguistics, and anthropology, where women achieved parity several decades ago. As the recipient of an NSF graduate research fellowship in linguistics, I have nothing against the NSF including social and behavioral sciences under its domain, and as a linguistics PhD, I would love for everyone to realize that linguistics is one of the sciences. Nonetheless, it's unlikely that the general readership of the Times would realize that these 'softer' sciences are part of the comparison set for CS. In fact, the graphic in this post comes from a New York Times op-ed inspired by the Larry Summer's 'Women scientists? ha!' controversy, and not surprisingly social and behavioral sciences don't make the list because no one is losing sleep over their female-to-male ratio.

Now, I admit that the percentage of women receiving bachelor's in CS is down from its peak in 1984 of 37%. But this means the real question of interest may not be why so few women are entering now, but why did so many women enter field in the mid 1980s. Maybe examining what briefly made CS attractive to women (and men) back then and comparing it to another boom-bust field like physics, like this far more insightful 2005 article in the Boston Globe did, could yield some insights on how to boost women's participation in all these fields which are so crucial to technological advancement and economic progress, but still so lacking in women.

Unfortunately, Stross's approach was to grossly oversimplify the problem of women's underrepresentation in science and engineering by ignoring the aspects of the data that didn't fit into his "Digital Domain" theme. Leaving us hapless readers to lament Where were his editors?

Saturday, November 22, 2008

Hating on David Brooks

Welcome to Valedictocracy, a cozy little blog where we unleash our inner know-it-alls on all that is irritating, misguided, and just plain dumb.

And, of course, there's nothing more irritating than David Brook's armchair (or salad bar) sociological categories: the bourgeois bohemians, the organization kids, patio man, and now the valedictocrats, all of which are imaginary creatures with no greater basis in the here and now than unicorns, hobbits, or moderate Republicans.

Nonetheless, like Brooks, I, for one, welcome our new Achievatron overlords. And, being a cautious, washed-up valedictorian myself, rather than being the change I want to see, in this blog I will merely criticize the foolishness I love to hate!

Stay tuned for more overeducated pontificating coming your way shortly...