I went to an interesting talk last week on why individuals don't choose to buy long-term care insurance. While the speaker did not have an answer to that question just yet (it's a work in progress), she did have a lot to say on the use of qualitative methods as a set up for and complement to statistical methods. In the past I've made fun of qualitative work as a "be all, end all" strategy in attacking a given research question ("its not representative," "it takes forever to do," "I don't believe things if there is no math or hard data," etc). But I do agree that qualitative work can help give direction to statistical analysis and aid in the interpretation of sempirical results.
Anyway, in explaining the mechanics behind the qualitative methodology, the speaker pointed out how sampling in qualitative methodology essentially obeys the law of diminishing returns (called the saturation principle, here). Basically, you keep adding to the sample until you stop learning anything new - when the marginal returns to interviewing approach zero. Apparently the majority of qualitative studies saturate somewhere between 25 and 30 subjects/interviewees.
I had a sudden flash of insight when I heard these numbers. The Central Limit Theorem (the big one) posits that the sum of a vector of random variables distributed with finite variance approaches a normal distribution for large values of n. Imagine a really screwed up probability distribution. Draw n numbers from it, and take the sum. Do it over and over and look at the distributions of the sums. Boom! Its looks normal! Its a beautiful result, and the proof is quite elegant, too.
The Central Limit Theorem appears to kick in around n of 30 or so. Thats whyI got so excited about the saturation numbers: its just interesting that two apparently distinct phenomena attain right around the same sample size. Obviously, I could be exhibiting a classical behavioral economics bias and attributing patterns to what are basically unrelated phenomena that just so happen to agree with one another. On the other hand, maybe there is more to it - something fundamental and deep.
Some more: If you like these kind of oddities and puzzles, you should read Fermat's Last Theorem by Simon Singh. It's one of the best books I've read in a long time. Basically it covers the 300+ year history of this annoying and outstanding math problem that kids can understand but adults (including Hall of Famers like Euler) could not solve for several centuries. The beast was laid to rest in 1993 by a Princeton mathematician who spent something like a decade of his life working on this problem and this problem alone. While the problem for a long time looked like some trivial curiousity, the Last Theorem ultimately speaks to some deep connections between branches of mathematics thought to be distinct.
The book is chock full of short biographies of all the mathemeticians who made contributions to solving the problem, interesting nuggets about number theory and the fundamental importance of prime numbers, irrational numbers, etc, and insights into how seemingly trivial mathematics could have mighty big things to say about the natural and physical world. It's a great read, and allows us normal folk to catch a glimpse into the beauty of mathematics.
Friday, November 30, 2007
Tuesday, November 27, 2007
How Can You Not Love Fantasy Football?
I've copied a recent post from our fantasy league discussion board below. When I realized how ridiculous it would sound to people who aren't part of our league (or are non-participants in fantasy sports in general), I started laughing and couldn't stop. I'm still laughing now.
Just to put it in context, we have twelve teams in our league and six playoff spots. This is the final week of our regular season. Three teams (myself included) have clinched playoff spots and a whopping seven teams, all 6-6, are fighting for the other three.
Here goes:
I don't know if we've ever had a week as exciting as this right before the playoffs. Each of the 6-6 teams could end up in the playoffs.
Homechickens has to win to get the 1st round bye.
Hufflepuff and Bum Bum are playing for the first 1st round bye.
Then it gets really interesting.
Harmonica and FightingIrish control their own destiny and are into the playoffs with a win.
Regal, Detroit, Drunken, and Buckeye are also competing with each other for points scored this week b/c they are all within 40 pts. of each other.
dags needs to win and have DetroitLions4eva lose to make the playoffs.
It's pretty cool b/c everyone has something to play for.
Cheer for my team!
Just to put it in context, we have twelve teams in our league and six playoff spots. This is the final week of our regular season. Three teams (myself included) have clinched playoff spots and a whopping seven teams, all 6-6, are fighting for the other three.
Here goes:
I don't know if we've ever had a week as exciting as this right before the playoffs. Each of the 6-6 teams could end up in the playoffs.
Homechickens has to win to get the 1st round bye.
Hufflepuff and Bum Bum are playing for the first 1st round bye.
Then it gets really interesting.
Harmonica and FightingIrish control their own destiny and are into the playoffs with a win.
Regal, Detroit, Drunken, and Buckeye are also competing with each other for points scored this week b/c they are all within 40 pts. of each other.
dags needs to win and have DetroitLions4eva lose to make the playoffs.
It's pretty cool b/c everyone has something to play for.
Cheer for my team!
Monday, November 26, 2007
Obesity in Developing Countries? Part II
More on the association between early life circumstances and later obesity. Check out this new working paper by Anne Case and Alicia Menendez on gender differences in obesity in South Africa. Here is the abstract (emphasis mine):
Globally, men and women face markedly different risks of obesity. In all but of handful of (primarily Western European) countries, obesity is more prevalent among women than men. In this paper, we examine several potential explanations for this phenomenon. We analyze differences between men and women in reports and effects of the proximate causes of obesity -- physical exertion and food intake -- and the underlying causes of obesity -- childhood and adult poverty, depression, and attitudes about obesity. We evaluate the evidence for each explanation using data collected in an African township outside of Cape Town. Three factors explain the greater obesity rates we find among women. Women who were nutritionally deprived as children are significantly more likely to be obese as adults, while men who were deprived as children face no greater risk. In addition, women of higher adult socioeconomic status are significantly more likely to be obese, which is not true for men. These two factors can fully explain the difference in obesity rates we find in our sample. Finally (and more speculatively), women's perceptions of an 'ideal' female body are larger than men's perceptions of the 'ideal' male body, and individuals with larger 'ideal' body images are significantly more likely to be obese.
Globally, men and women face markedly different risks of obesity. In all but of handful of (primarily Western European) countries, obesity is more prevalent among women than men. In this paper, we examine several potential explanations for this phenomenon. We analyze differences between men and women in reports and effects of the proximate causes of obesity -- physical exertion and food intake -- and the underlying causes of obesity -- childhood and adult poverty, depression, and attitudes about obesity. We evaluate the evidence for each explanation using data collected in an African township outside of Cape Town. Three factors explain the greater obesity rates we find among women. Women who were nutritionally deprived as children are significantly more likely to be obese as adults, while men who were deprived as children face no greater risk. In addition, women of higher adult socioeconomic status are significantly more likely to be obese, which is not true for men. These two factors can fully explain the difference in obesity rates we find in our sample. Finally (and more speculatively), women's perceptions of an 'ideal' female body are larger than men's perceptions of the 'ideal' male body, and individuals with larger 'ideal' body images are significantly more likely to be obese.
Sunday, November 25, 2007
Root for the Underdog of the Season!
For the last nine years, I've been playing Yahoo! Fantasy Football with the same group of college and high school buddies. In this time span, I've only been to the playoffs in four times and have yet to win a single playoff game. I fielded my best team in 2002, destroying the opposition to go 10-3 and finish regular season number one. Then, in the flameout of all flameouts, I lost each of my three playoff games and finished in 6th place.
Basically, as the "owner" of my team, I would fire myself as GM and Coach. I might as well set up the team and outsource all the decision making to someone who knows better.
Anyway, this season, with two games left in the regular season, I am sitting in second place at 8-3, having scored more points that each of the teams below me, and just five points off the pace of the first place squad. I've clinched a playoff spot, and I am hoping to win it all.
I think you should root for my team this year, especially because since my squad is the kind of underdog everyone would want to root for. Here is why:
1) I've overcome adversity at multiple points this season - I lost Ronnie Brown, who was an early season fantasy hoss, for the year, Jevon Walker for most of the season, and David Gerrard for a crucial four game stretch. Despite this, I keep winning. I attribute this to my unusually good waiver wire strategies (see 3).
2) My squad is made up of a lot of cast-offs and feel good stories - For example, my starting QBs are Jeff Garcia, a journeyman, elderly statesman, and David Gerrard, who wasn't even supposed to start when I drafted him. My backup QB is Vinny Testerverde, a guy my father remembers seeing play when he was in grad school. My second starting RB is Jesse Chatman, Ronnie Brown's replacement in Miami who kept getting kicked off of his past teams for being overweight. My defense was drawn entirely off the waiver wire (I missed the live draft when I was in South Africa). Finally, even my lovable uber-star, the incomparable LaDanian Tomlinson, is having an off year (by his standards, anyway).
3) The owner really needs this win - My college roommate, a three or four time champion, keeps pointing out how I've historically sucked at fantasy. In the past, other owners have criticized admittedly stupid roster moves I've made (for every mid season trade for Larry Johnson, I've drafted rookie WRs in the fourth round). I need to win both to earn respect and to offset what has been a ridiculously dry semester of research.
Also, did I mention that I haven't won a playoff game in nine years? There is only one way to describe that: hapless.
4) Finally, my team is named Hufflepuff's Cup, in honor of the kind but ultimately unremarkable Hogwarts House. Its funny how my team has turned out to be just like them: no stars, just solid performers who put their hearts and bodies on the line for me every week. How can you root against a team like that!?
So, for the next five weeks, root for Hufflepuff's Cup. It's like cheering for Rocky or those Chak De India girls: its a tough ride but, in the end, I think you'll be glad you stuck with 'em.
Basically, as the "owner" of my team, I would fire myself as GM and Coach. I might as well set up the team and outsource all the decision making to someone who knows better.
Anyway, this season, with two games left in the regular season, I am sitting in second place at 8-3, having scored more points that each of the teams below me, and just five points off the pace of the first place squad. I've clinched a playoff spot, and I am hoping to win it all.
I think you should root for my team this year, especially because since my squad is the kind of underdog everyone would want to root for. Here is why:
1) I've overcome adversity at multiple points this season - I lost Ronnie Brown, who was an early season fantasy hoss, for the year, Jevon Walker for most of the season, and David Gerrard for a crucial four game stretch. Despite this, I keep winning. I attribute this to my unusually good waiver wire strategies (see 3).
2) My squad is made up of a lot of cast-offs and feel good stories - For example, my starting QBs are Jeff Garcia, a journeyman, elderly statesman, and David Gerrard, who wasn't even supposed to start when I drafted him. My backup QB is Vinny Testerverde, a guy my father remembers seeing play when he was in grad school. My second starting RB is Jesse Chatman, Ronnie Brown's replacement in Miami who kept getting kicked off of his past teams for being overweight. My defense was drawn entirely off the waiver wire (I missed the live draft when I was in South Africa). Finally, even my lovable uber-star, the incomparable LaDanian Tomlinson, is having an off year (by his standards, anyway).
3) The owner really needs this win - My college roommate, a three or four time champion, keeps pointing out how I've historically sucked at fantasy. In the past, other owners have criticized admittedly stupid roster moves I've made (for every mid season trade for Larry Johnson, I've drafted rookie WRs in the fourth round). I need to win both to earn respect and to offset what has been a ridiculously dry semester of research.
Also, did I mention that I haven't won a playoff game in nine years? There is only one way to describe that: hapless.
4) Finally, my team is named Hufflepuff's Cup, in honor of the kind but ultimately unremarkable Hogwarts House. Its funny how my team has turned out to be just like them: no stars, just solid performers who put their hearts and bodies on the line for me every week. How can you root against a team like that!?
So, for the next five weeks, root for Hufflepuff's Cup. It's like cheering for Rocky or those Chak De India girls: its a tough ride but, in the end, I think you'll be glad you stuck with 'em.
Thursday, November 22, 2007
Thanksgiving: A Good Time to Think About Obesity
Related to my earlier post, I just came a recent article about the driving forces behind obesity in the developed world. Here is a link to a non-technical summary of the paper (a link to the actual article is nested within) and here is nice analytic piece by the Healthcare Economist.
The major take home point is that most (over 90%) of the increase in obesity seems to be driven by the fact that people are eating more now than before. The authors of the paper contend that the other side of the equation, decreased caloric expenditure, is quantitatively less important, though still non-trivial.
The main question then is: why are people consuming more calories? The theories out there to explain this generally fall into two categories:
1) high monetary and opportunity costs of healthy foods relative to unhealthy foods (the proliferation of fast food joints, putative effects of US agricultural subsidies, etc)
2) lower costs of calories in general due to improvements in agricultural technology
I don't know if anyone has really been able to assess the relative (or even absolute) importance of these explanations in the data. I do know that obesity is a scorching hot area of research and that the coming years should provide us with a slew of new research evidence for us to feast on. A good example: a new working paper assessing the fast food joint-obesity link.
In the meantime, Happy Thanksgiving and enjoy the inevitable feast!
The major take home point is that most (over 90%) of the increase in obesity seems to be driven by the fact that people are eating more now than before. The authors of the paper contend that the other side of the equation, decreased caloric expenditure, is quantitatively less important, though still non-trivial.
The main question then is: why are people consuming more calories? The theories out there to explain this generally fall into two categories:
1) high monetary and opportunity costs of healthy foods relative to unhealthy foods (the proliferation of fast food joints, putative effects of US agricultural subsidies, etc)
2) lower costs of calories in general due to improvements in agricultural technology
I don't know if anyone has really been able to assess the relative (or even absolute) importance of these explanations in the data. I do know that obesity is a scorching hot area of research and that the coming years should provide us with a slew of new research evidence for us to feast on. A good example: a new working paper assessing the fast food joint-obesity link.
In the meantime, Happy Thanksgiving and enjoy the inevitable feast!
Wednesday, November 21, 2007
Obesity in Developing Countries?
I'm doing some research on nutrition, child health and public programs in Mexico and, in the process of looking for a paper, came across this interesting article in JAMA about obesity among the Mexican poor. It turns out that obesity rates among the poor in Mexico rival those in the United States (obesity rates in general have followed a similar trend to the US, with large increases occurring between the 1980s and 1990s). This is especially interesting given that poor Mexicans live in conditions similar to the developing world, where obesity is only common among the upper strata of the population (though this is starting to change; exs: rural India and China). Doubly interesting is the growing phenomenon of young children who are both stunted and overweight, an interesting paradox of early life deprivation, on the one hand, and excess on the other.
Causes for the rapid increase in Mexican obesity are likely similar to those in the U.S.: changes in technology and policy that alter the balance between caloric input and output. For example, this paper notes that increasingly sedentary lifestyles and changes in diet are likely largely responsible for increased fattening. While I'm not sure if anyone has really stepped in and done some kind of accounting exercise or decomposition trying to explain time-trends in Mexican obesity, this doesn't seem to be a bad conjecture to make given the evidence.
We know from the United States that the poor are much more susceptible to these secular trends: healthy food appears to be a normal good, fast foods inferior, and exercise a luxury good. At least from what I can gather from the Mexican evidence, this is likely to be the case south of the border, as well. But are there reasons, external to basic economic theory, that might explain why the poor tend to be more obese?
There are some interesting biological theories that suggest that individuals who are deprived of nutrition while in the womb but exposed to relative abundance thereafter are more likely to become obese, diabetic, and develop cardiovascular disease. The idea is that fetus' adapt to scarcity, which results in permanent metabolic/endocrine changes. While these changes are advantageous in scarcity, the might actually be maladaptive in situations of relative abundance. Some evidence supporting this theory in (laboratory) animal and human populations can be found on pp 44-45 of this very thorough survey on the economics of health and socioeconomic status in developing countries (a must read for all interested in health and development as an area of research).
So tying this back to poverty: poor individuals are either more likely to be born in situations of deprivation or, in the case of economy wide shocks, unable to smooth their consumption so as to prevent under-investments in their kids during the fetal period and early childhood years. Faced with falling (unhealthy) food prices and secular changes in the level of human activity, if the biology behind the aforementioned theory is sound, these individuals might be doubly affected in terms of developing metabolic and cardiovascular conditions. Notice that the theory would also explain the stunted/overweight kids: stunting is a result of the fetal adaptation to scarcity, and overweight the result of exposure to abundance.
While some work on the Dutch and Chinese famines support this hypothesis (see the previous link), I am not aware of any other work looking the interaction between early life conditions/endowments and secular changes in technology. As a result, and since the marginal cost of adding this on as a project is low (I am using a well-suited Mexican dataset for another purpose, anyway), I've decided to have a go at the theory and see what I find. I'll keep you posted.
Causes for the rapid increase in Mexican obesity are likely similar to those in the U.S.: changes in technology and policy that alter the balance between caloric input and output. For example, this paper notes that increasingly sedentary lifestyles and changes in diet are likely largely responsible for increased fattening. While I'm not sure if anyone has really stepped in and done some kind of accounting exercise or decomposition trying to explain time-trends in Mexican obesity, this doesn't seem to be a bad conjecture to make given the evidence.
We know from the United States that the poor are much more susceptible to these secular trends: healthy food appears to be a normal good, fast foods inferior, and exercise a luxury good. At least from what I can gather from the Mexican evidence, this is likely to be the case south of the border, as well. But are there reasons, external to basic economic theory, that might explain why the poor tend to be more obese?
There are some interesting biological theories that suggest that individuals who are deprived of nutrition while in the womb but exposed to relative abundance thereafter are more likely to become obese, diabetic, and develop cardiovascular disease. The idea is that fetus' adapt to scarcity, which results in permanent metabolic/endocrine changes. While these changes are advantageous in scarcity, the might actually be maladaptive in situations of relative abundance. Some evidence supporting this theory in (laboratory) animal and human populations can be found on pp 44-45 of this very thorough survey on the economics of health and socioeconomic status in developing countries (a must read for all interested in health and development as an area of research).
So tying this back to poverty: poor individuals are either more likely to be born in situations of deprivation or, in the case of economy wide shocks, unable to smooth their consumption so as to prevent under-investments in their kids during the fetal period and early childhood years. Faced with falling (unhealthy) food prices and secular changes in the level of human activity, if the biology behind the aforementioned theory is sound, these individuals might be doubly affected in terms of developing metabolic and cardiovascular conditions. Notice that the theory would also explain the stunted/overweight kids: stunting is a result of the fetal adaptation to scarcity, and overweight the result of exposure to abundance.
While some work on the Dutch and Chinese famines support this hypothesis (see the previous link), I am not aware of any other work looking the interaction between early life conditions/endowments and secular changes in technology. As a result, and since the marginal cost of adding this on as a project is low (I am using a well-suited Mexican dataset for another purpose, anyway), I've decided to have a go at the theory and see what I find. I'll keep you posted.
Sunday, November 18, 2007
Review: Chris Cornell 2007 North America Tour
A few weeks ago, I decided to take a five minute break and visit rock-icon Chris Cornell's website. In July, I was lamenting the fact that I would be unable to attend any of his summer concerts, set up to promote his new solo album Carry On, because of a trip to India and South Africa. Actually, I wasn't lamenting it all that much since I was excited to go abroad and Carry On was pretty bad. Anyway, I had heard a rumor that Chris would be starting a new North America tour and wanted to get a sense of whether I would be able to go to any of the concerts.
To my surprise, Chris was set to play at Northern Lights in Clifton Park, NY, on Nov. 10th. The venue is literally 0.9 miles from my parents' place! Within five minutes, I had already bought my tickets and had told pretty much everyone I know that I would be going to the concert. According to the website, Cornell and his touring band would be playing hits from his 13 album career, spanning bands like Soundgarden, Temple of the Dog and Audioslave, as well as some of his solo work.
If that sounds incredible to you, get this: the concert surpassed my expectations on every level. The opening act, the multi-racial Earl Greyhound from New York City, brought in some hard, soul power to the proceedings. A nice little appetizer for ridiculously incredible stuff that was to come.
Cornell made a grand entrance with "Let Me Drown", from the Soundgarden album, Superunknown. Standing at 40+ years, mellowed out, and in the middle of a transition into an adult contemporary like-solo career, Cornell still came out and worked it like old times. A six song acoustic set (which I really enjoyed), including "Call me a Dog," "Like a Stone," "I am the Highway," and his now infamous rendition of "Billie Jean," along with "Arms Around Your Love" was the mellowest this show got. The rest of show featured Cornell screaming and slamming through vocally demanding selections like "Outshined," "Jesus Christ Pose," "Rusty Cage," "Ty Cobb," "Cochise," and "Show Me How to Live."
All in all, he ended up performing 28 songs, with a lot of Soundgarden and Audioslave for the (relatively) older and younger fans alike. I'm guessing its got to be hard to please everyone when sampling from your greatest hits spanning a 20+ year period. It's a testament to the quality, depth and variety of this concert that my only complaint was that Cornell did not perform "Burden in My Hand." No worries, though: the multi-song encore more than made that little point irrelevant.
I could go on all day praising this concert. Instead of doing that, though, I'm going to let the proceedings speak for themselves. Check out this snap and video clip. The sound quality on the latter is quite suspect, mainly because I was so close to the stage and, therefore, the speakers. I hope you can make out that this is a snippet from "Spoonman." Enjoy.
To my surprise, Chris was set to play at Northern Lights in Clifton Park, NY, on Nov. 10th. The venue is literally 0.9 miles from my parents' place! Within five minutes, I had already bought my tickets and had told pretty much everyone I know that I would be going to the concert. According to the website, Cornell and his touring band would be playing hits from his 13 album career, spanning bands like Soundgarden, Temple of the Dog and Audioslave, as well as some of his solo work.
If that sounds incredible to you, get this: the concert surpassed my expectations on every level. The opening act, the multi-racial Earl Greyhound from New York City, brought in some hard, soul power to the proceedings. A nice little appetizer for ridiculously incredible stuff that was to come.
Cornell made a grand entrance with "Let Me Drown", from the Soundgarden album, Superunknown. Standing at 40+ years, mellowed out, and in the middle of a transition into an adult contemporary like-solo career, Cornell still came out and worked it like old times. A six song acoustic set (which I really enjoyed), including "Call me a Dog," "Like a Stone," "I am the Highway," and his now infamous rendition of "Billie Jean," along with "Arms Around Your Love" was the mellowest this show got. The rest of show featured Cornell screaming and slamming through vocally demanding selections like "Outshined," "Jesus Christ Pose," "Rusty Cage," "Ty Cobb," "Cochise," and "Show Me How to Live."
All in all, he ended up performing 28 songs, with a lot of Soundgarden and Audioslave for the (relatively) older and younger fans alike. I'm guessing its got to be hard to please everyone when sampling from your greatest hits spanning a 20+ year period. It's a testament to the quality, depth and variety of this concert that my only complaint was that Cornell did not perform "Burden in My Hand." No worries, though: the multi-song encore more than made that little point irrelevant.
I could go on all day praising this concert. Instead of doing that, though, I'm going to let the proceedings speak for themselves. Check out this snap and video clip. The sound quality on the latter is quite suspect, mainly because I was so close to the stage and, therefore, the speakers. I hope you can make out that this is a snippet from "Spoonman." Enjoy.
Friday, November 16, 2007
Public Health in India: Some New Data
The Ministry of Health and Public Welfare in New Delhi recently released data from the third National Family Health Survey (NHFS-3), based on a nationally representative sample of women aged 15-49 year women. The survey provides information on health and welfare for nearly 200,000 women, as well as their spouses and children. For a variety of reasons, this survey is a potential gold mine for public health, health economics, and public policy research projects. You can have a look at the details here. The summary report, which is very thorough and serves as an excellent reference for all things public health in India, is available via the same link. It is essential reading for all Indophiles, whatever your discipline or persuasion may be.
I've glanced through the summary report myself and have found some really interesting things (some of which will likely serve as fodder for research in the coming months). Here is a sampling:
1) The NFHS-3 is the first large scale all-India survey to include HIV testing. Surprisingly, despite local resistance in states like Nagaland, nearly 82% of eligible women and men were tested. This is a lot higher than I would have imagined given stigma around HIV/AIDS combined with voluntary testing. The survey finds that 0.28% of adults 15-49 have tested positive for HIV, that the prevalence of HIV is much higher in urban areas and among men. Also, HIV in India does not seem to discriminate by caste or level of wealth. In fact, the highest positive rate is among one of the top wealth quintiles in the sample.
2) Over 70% of children under 5 are considered to be stunted (i.e., below 2 sd from the median height for a child of given gender and age in months). However, only 32.9% of all children in the sample received services from the Integrated Child Development Services (ICDS) program, a village level intervention designed to provide basic health, nutrition and educational services mothers and young children, which now has very wide coverage in India. This isn't an issue of coverage: that 32.9% figure applies to all children who live in an area with ICDS facilities. I find this really interesting. ICDS offers free services and free food and children are malnourished. So why aren't more mothers taking it up? There are a variety of reasons why this could happen: ICDS is perceived to be ineffective; supply-side problems, such as failure to staff the clinics; high opportunity costs to attending ICDS (long-queues, remote locations); lack of knowledge among mothers or heterogeneous treatment effects that induce self-selection among certain classes of families. I think it would be interesting to compute (heterogeneous?) returns to the ICDS program and get a sense of why people are not going.
3) Less than half of all households in India use adequately iodized salt. This could have tremendous long-term consequences, especially for young children. Check out this important and interesting paper by Erica Field, et al, for more information.
4) The data is representative at the state level as well, and its always fun to compare how different states do with respect to various health indicators. Obviously, there is a great deal of variance among states in population health status.
5) There is plenty of other interesting information on anemia among men, women and children, female bargaining power and domestic violence, knowledge and attitudes about HIV/AIDS, household socioeconomic status, and so forth. Again, its a pretty rich survey for public health stuff, and I encourage you to check it out.
I've glanced through the summary report myself and have found some really interesting things (some of which will likely serve as fodder for research in the coming months). Here is a sampling:
1) The NFHS-3 is the first large scale all-India survey to include HIV testing. Surprisingly, despite local resistance in states like Nagaland, nearly 82% of eligible women and men were tested. This is a lot higher than I would have imagined given stigma around HIV/AIDS combined with voluntary testing. The survey finds that 0.28% of adults 15-49 have tested positive for HIV, that the prevalence of HIV is much higher in urban areas and among men. Also, HIV in India does not seem to discriminate by caste or level of wealth. In fact, the highest positive rate is among one of the top wealth quintiles in the sample.
2) Over 70% of children under 5 are considered to be stunted (i.e., below 2 sd from the median height for a child of given gender and age in months). However, only 32.9% of all children in the sample received services from the Integrated Child Development Services (ICDS) program, a village level intervention designed to provide basic health, nutrition and educational services mothers and young children, which now has very wide coverage in India. This isn't an issue of coverage: that 32.9% figure applies to all children who live in an area with ICDS facilities. I find this really interesting. ICDS offers free services and free food and children are malnourished. So why aren't more mothers taking it up? There are a variety of reasons why this could happen: ICDS is perceived to be ineffective; supply-side problems, such as failure to staff the clinics; high opportunity costs to attending ICDS (long-queues, remote locations); lack of knowledge among mothers or heterogeneous treatment effects that induce self-selection among certain classes of families. I think it would be interesting to compute (heterogeneous?) returns to the ICDS program and get a sense of why people are not going.
3) Less than half of all households in India use adequately iodized salt. This could have tremendous long-term consequences, especially for young children. Check out this important and interesting paper by Erica Field, et al, for more information.
4) The data is representative at the state level as well, and its always fun to compare how different states do with respect to various health indicators. Obviously, there is a great deal of variance among states in population health status.
5) There is plenty of other interesting information on anemia among men, women and children, female bargaining power and domestic violence, knowledge and attitudes about HIV/AIDS, household socioeconomic status, and so forth. Again, its a pretty rich survey for public health stuff, and I encourage you to check it out.
Saturday, November 10, 2007
The Salience of Personal Experience
I had an interesting discussion with my mom today about a new working paper on arranged marriage. The basic finding in the paper is that, among a large sample of families in Mumbai, India, men who find their partners via arranged marriage are much less likely to marry college-educated and/or working women. The paper makes a valiant attempt to show that this is being driven by arranged marriage specific parental preferences rather than omitted variable bias.
My mom, an extremely intelligent person who, like all mothers, "knows best", had the following comments:
1) I am not sure whether this finding would hold up in other parts of India.
2) I don't buy the finding because I know so and so, and they married someone highly educated through an arranged marriage process.
My mom makes a valid statistical argument with the first point: underlying parameters may indeed differ across populations. There is no way to know whether these findings replicate in Chennai without getting data and giving it a go. Go mom.
Its the second point that interests me more. Regression coefficients basically give you some average effect, conditional on whatever else you control for. Put less loosely, the regression model in this paper tells you the expected change in spousal education for a given change in type of marriage holding constant family background, income, etc. While any handful of individuals might behave contrary to the prediction, these folks are averaged out the the large number of people who follow rank-and-file.
What's interesting is how my mom completely rejected the average effect based on her experience with a few relatives of ours. I think this is an extremely common phenomenon and speaks towards to power of personal experience in shaping expectations and behavior. No doubt, behavioral economics probably has a lot to say about this kind of thinking (which I am prone to on almost a daily basis!).
The whole episode reminded me of a comment made by Yale School of Management behavioral economist Keith Chen in our departmental seminar. Paraphrasing a bit, his point was that people are much more likely to rely on their next door neighbor's experience in making a decision to buy, say, a car rather than Consumer Reports. This is irrational since the former represents a single draw from a distribution of reviews, whereas the latter gives the expected value of this underlying distribution.
My mom, an extremely intelligent person who, like all mothers, "knows best", had the following comments:
1) I am not sure whether this finding would hold up in other parts of India.
2) I don't buy the finding because I know so and so, and they married someone highly educated through an arranged marriage process.
My mom makes a valid statistical argument with the first point: underlying parameters may indeed differ across populations. There is no way to know whether these findings replicate in Chennai without getting data and giving it a go. Go mom.
Its the second point that interests me more. Regression coefficients basically give you some average effect, conditional on whatever else you control for. Put less loosely, the regression model in this paper tells you the expected change in spousal education for a given change in type of marriage holding constant family background, income, etc. While any handful of individuals might behave contrary to the prediction, these folks are averaged out the the large number of people who follow rank-and-file.
What's interesting is how my mom completely rejected the average effect based on her experience with a few relatives of ours. I think this is an extremely common phenomenon and speaks towards to power of personal experience in shaping expectations and behavior. No doubt, behavioral economics probably has a lot to say about this kind of thinking (which I am prone to on almost a daily basis!).
The whole episode reminded me of a comment made by Yale School of Management behavioral economist Keith Chen in our departmental seminar. Paraphrasing a bit, his point was that people are much more likely to rely on their next door neighbor's experience in making a decision to buy, say, a car rather than Consumer Reports. This is irrational since the former represents a single draw from a distribution of reviews, whereas the latter gives the expected value of this underlying distribution.
Thursday, November 8, 2007
Another U.S. Health Care System Myth?
This time its about uncompensated care. Here is a link to the paper in question, by economists Jon Gruber and David Rodriguez. Here is the abstract:
The magnitude of provider uncompensated care has become an important public policy issue. Yet existing measures of uncompensated care are flawed because they compare uninsured payments to list prices, not to the prices actually paid by the insured. We address this issue using a novel source of data from a vendor that processes financial data for almost 4000 physicians. We measure uncompensated care as the net amount that physicians lose by lower payments from the uninsured than from the insured. Our best estimate is that physicians provide negative uncompensated care to the uninsured, earning more on uninsured patients than on insured patients with comparable treatments. Even our most conservative estimates suggest that uncompensated care amounts to only 0.8% of revenues, or at most $3.2 billion nationally. These results highlight the important distinction between charges and payments, and point to the need for a re-definition of uncompensated care in the health sector going forward.
The magnitude of provider uncompensated care has become an important public policy issue. Yet existing measures of uncompensated care are flawed because they compare uninsured payments to list prices, not to the prices actually paid by the insured. We address this issue using a novel source of data from a vendor that processes financial data for almost 4000 physicians. We measure uncompensated care as the net amount that physicians lose by lower payments from the uninsured than from the insured. Our best estimate is that physicians provide negative uncompensated care to the uninsured, earning more on uninsured patients than on insured patients with comparable treatments. Even our most conservative estimates suggest that uncompensated care amounts to only 0.8% of revenues, or at most $3.2 billion nationally. These results highlight the important distinction between charges and payments, and point to the need for a re-definition of uncompensated care in the health sector going forward.
Wednesday, November 7, 2007
The U.S. Health Care System: Not So Bad?
I am currently serving as a TA for two courses, a basic undergrad health economics class given through the economics department and a health policy class for MPH students via the School of Public Health. At the beginning of the semester, the professors in each class put forth the following question: "How many of you think that the American health care system gives good value for the dollar?" Surprisingly, about 1/3 of the undergrads answered "yes." Not surprisingly, the public health-ers unanimously answered "no."
I think there are two things to take from this. First, there is a great deal of self-selection on the margin of political leanings in public health. Most MPH students tend to identify with democrats/liberals (or, in one of my more cynical moments, "pink-os"), which probably is what induces them to pursue a service-oriented field like public health in the first place. (I'm not sure if the causality works the other way: does learning about public health shift people's voting preferences to the left?).
Second, and most germane to this post, is that, despite what Michael Moore says, not everyone thinks the U.S. health care system is a complete disaster. Slowly but surely, some recent press and research work suggests that the American system isn't really as bad as it seems when making general comparisons with systems in other OECD countries.
For some insight into this, check out recent New York Times article by Greg Mankiw. It is actually the post that I wanted to write and had already written part of before finding out I was scooped. Given that I was about the say the same thing, I think his commentary is very sensible. Here are the major points (I'm not going to give too much away, so as not to destroy any incentives to read the real thing):
1) Cross-country differences in infant mortality rates and life expectancies are mismeasured and overstated when judging different health systems.
2) The 47 million uninsured statistic that everyone quotes masks a lot of things that actually aren't very worrisome, at all.
3) Rising health care costs may be a sign of progress rather than impending doom. At the very least, putting a value judgment on that 16% of GDP tidbit is misguided.
These points don't just stem from conservative, free-market dogmas. Rather, they should be taken seriously for their attention to measurement issues and economic principles. It isn't the first time that alternate, less pernicious interpretations can be given to stylized facts that initially seem quite alarming. Check out an earlier post for another example of this, which also happens to be drawn from the health care arena.
The obvious bottom line: we need to learn from both sides of the health care debate in order to make reasonable policies.
I think there are two things to take from this. First, there is a great deal of self-selection on the margin of political leanings in public health. Most MPH students tend to identify with democrats/liberals (or, in one of my more cynical moments, "pink-os"), which probably is what induces them to pursue a service-oriented field like public health in the first place. (I'm not sure if the causality works the other way: does learning about public health shift people's voting preferences to the left?).
Second, and most germane to this post, is that, despite what Michael Moore says, not everyone thinks the U.S. health care system is a complete disaster. Slowly but surely, some recent press and research work suggests that the American system isn't really as bad as it seems when making general comparisons with systems in other OECD countries.
For some insight into this, check out recent New York Times article by Greg Mankiw. It is actually the post that I wanted to write and had already written part of before finding out I was scooped. Given that I was about the say the same thing, I think his commentary is very sensible. Here are the major points (I'm not going to give too much away, so as not to destroy any incentives to read the real thing):
1) Cross-country differences in infant mortality rates and life expectancies are mismeasured and overstated when judging different health systems.
2) The 47 million uninsured statistic that everyone quotes masks a lot of things that actually aren't very worrisome, at all.
3) Rising health care costs may be a sign of progress rather than impending doom. At the very least, putting a value judgment on that 16% of GDP tidbit is misguided.
These points don't just stem from conservative, free-market dogmas. Rather, they should be taken seriously for their attention to measurement issues and economic principles. It isn't the first time that alternate, less pernicious interpretations can be given to stylized facts that initially seem quite alarming. Check out an earlier post for another example of this, which also happens to be drawn from the health care arena.
The obvious bottom line: we need to learn from both sides of the health care debate in order to make reasonable policies.
Monday, November 5, 2007
Developing an Area is Hard
There has been a good deal of talk recently about the UN Millennium Village project. Spearheaded by rock-star economist Jeffrey Sachs, the project is a direct extension of the ideas put forth in his book The End of Poverty. Here is a good description of the basic aims:
The Millennium Project is trying to show how a few simple reforms, seven in all, can substantially improve lives and provide livelihoods. These are: fertiliser and seed to improve food yield; anti-malarial bed nets; improved water sources; diversification from staple into cash crops; a school feeding programme; deworming for all; and the introduction of new technologies, such as energy-saving stoves and mobile phones.
There are around 12 such villages in existence now, with the hope that the program will be expanded to over 1000 villages by 2009. Furthermore, Sachs and co. look to scale-up village-level interventions so as to generate "trickle-up" returns for districts and perhaps even countries. While Sachs himself seems to agree that many of these interventions may not be sustainable (i.e., they will require constant external funding to continue in place), the UN website for the project spends a good deal of time talking about "local ownership." This is basically a fancy way of saying that the average villager Joe and Jane will be able to have a say in the interventions, so as to tailor the program in ways that best resonate with the community. "Local ownership" is also a buzzword used to describe how external funded programs can become sustainable in the long-run: even after the donors leave, individuals in the village are left with the resources, expertise and desire to continue the efforts.
Time will tell whether the project goals are met. But it's always fun to speculate and form expectations about what might actually happen. On the one hand, the recent reviews about the millennium villages have been positive and, at times, quite breathtaking. On the other hand, others agree with this Marginal Revolution post and believe that the project will be difficult to scale up and sustain in over time.
Why exactly might such programs be hard to sustain? Obviously, there are a multitude of reasons. Some really interesting recent work can be used a lens to understand the roadblocks a bit more.
1) One good example is a provocatively titled paper by economists Michael Kremer and Ted Miguel called "The Illusion of Sustainability." This paper is a follow up on their classic experimental study on the economic impacts of deworming in Kenya. The basic idea is that deworming has externalities: treating some people provides benefits for everyone since some links in the transmission chain are now eliminated. In the "Illusion" paper, the authors look at four traditionally touted ways to promote sustainability and see whether these are effective in inducing people to take up deworming drugs and best practices. Learning from peers (some of whom were experimentally assigned to deworming in the original study) actually led to lower take-up, perhaps because, in a public goods world, individuals realize that the private benefit (which is less than the societal benefit because of the externality) of taking the drug is lower than the cost (side effects, etc). They also find that cost-sharing, educational interventions, and community mobilization efforts (i.e., encouraging "local ownership") did not work, either.
Miguel and Kremer go on to finish with a short discourse on why aid agencies might focus on sustainability even when such a goal is impossible. That alone is worth the price of admission here.
2) This next paper shows how well intentioned interventions can have unintended consequences. Its a clever study, and good reading for grad students or econophiles given the very intuitive and powerful theoretical section. I'll let the author explain the results himself, as the abstract is very transparent:
Water supply improvements are a frequent policy response to endemic diarrhea in developing countries. However, these interventions may unintentionally cause community sanitation to worsen. Such a response could occur because improved water supplies mitigate the consequences of poor sanitation for the community. Since sanitary behaviors have large externalities, the negative health impact of this endogenous response may overwhelm the direct benefit of clean water. This paper shows how the expansion of municipal piped water in Metro Cebu, the Philippines has exacerbated public defecation, garbage disposal, and diarrhea. I rely on instrumental variables and household fixed effects to rule out non-causal explanations for these results, and find that a neighborhood’s complete adoption of piped water increases the likelihood of observing excrement or garbage by 15-30 percent. Such a change increases diarrhea incidence by 35-40 percent.
3) Santosh forwarded me an interesting study by Abhijit Banerjee, Esther Duflo, and Rachel Glennerster, about an experimental intervention run amok in India. I wasn't able to find a link for this, but I will post the abstract here. The basic message? Existing governing and administration structures need to be brought into the intervention decision and implementation
process before they become a hindrance. If the stake-holders aren't participating (or are indifferent), you've got an uphill task.
The Indian Health Care system is plagued by high staff absence; low effort by the providers; and limited use by potential beneficiaries, who prefer private alternatives. This paper reports the results of an experiment carried out with a district administration and a nongovernmental organization (NGO). The presence of government nurses in government public health facilities (sub-centers and aid-posts) was recorded by the NGO, and the government took steps to punish the worst delinquents. Initially, the monitoring system was extremely effective. This shows that nurses are responsive to financial incentives. But after a few months, the local health administration appears to have undermined the scheme from the inside, by letting the nurses claim an increasing number of “exempt days.” Eighteen months after its inception, the program had become completely ineffective.
The Millennium Project is trying to show how a few simple reforms, seven in all, can substantially improve lives and provide livelihoods. These are: fertiliser and seed to improve food yield; anti-malarial bed nets; improved water sources; diversification from staple into cash crops; a school feeding programme; deworming for all; and the introduction of new technologies, such as energy-saving stoves and mobile phones.
There are around 12 such villages in existence now, with the hope that the program will be expanded to over 1000 villages by 2009. Furthermore, Sachs and co. look to scale-up village-level interventions so as to generate "trickle-up" returns for districts and perhaps even countries. While Sachs himself seems to agree that many of these interventions may not be sustainable (i.e., they will require constant external funding to continue in place), the UN website for the project spends a good deal of time talking about "local ownership." This is basically a fancy way of saying that the average villager Joe and Jane will be able to have a say in the interventions, so as to tailor the program in ways that best resonate with the community. "Local ownership" is also a buzzword used to describe how external funded programs can become sustainable in the long-run: even after the donors leave, individuals in the village are left with the resources, expertise and desire to continue the efforts.
Time will tell whether the project goals are met. But it's always fun to speculate and form expectations about what might actually happen. On the one hand, the recent reviews about the millennium villages have been positive and, at times, quite breathtaking. On the other hand, others agree with this Marginal Revolution post and believe that the project will be difficult to scale up and sustain in over time.
Why exactly might such programs be hard to sustain? Obviously, there are a multitude of reasons. Some really interesting recent work can be used a lens to understand the roadblocks a bit more.
1) One good example is a provocatively titled paper by economists Michael Kremer and Ted Miguel called "The Illusion of Sustainability." This paper is a follow up on their classic experimental study on the economic impacts of deworming in Kenya. The basic idea is that deworming has externalities: treating some people provides benefits for everyone since some links in the transmission chain are now eliminated. In the "Illusion" paper, the authors look at four traditionally touted ways to promote sustainability and see whether these are effective in inducing people to take up deworming drugs and best practices. Learning from peers (some of whom were experimentally assigned to deworming in the original study) actually led to lower take-up, perhaps because, in a public goods world, individuals realize that the private benefit (which is less than the societal benefit because of the externality) of taking the drug is lower than the cost (side effects, etc). They also find that cost-sharing, educational interventions, and community mobilization efforts (i.e., encouraging "local ownership") did not work, either.
Miguel and Kremer go on to finish with a short discourse on why aid agencies might focus on sustainability even when such a goal is impossible. That alone is worth the price of admission here.
2) This next paper shows how well intentioned interventions can have unintended consequences. Its a clever study, and good reading for grad students or econophiles given the very intuitive and powerful theoretical section. I'll let the author explain the results himself, as the abstract is very transparent:
Water supply improvements are a frequent policy response to endemic diarrhea in developing countries. However, these interventions may unintentionally cause community sanitation to worsen. Such a response could occur because improved water supplies mitigate the consequences of poor sanitation for the community. Since sanitary behaviors have large externalities, the negative health impact of this endogenous response may overwhelm the direct benefit of clean water. This paper shows how the expansion of municipal piped water in Metro Cebu, the Philippines has exacerbated public defecation, garbage disposal, and diarrhea. I rely on instrumental variables and household fixed effects to rule out non-causal explanations for these results, and find that a neighborhood’s complete adoption of piped water increases the likelihood of observing excrement or garbage by 15-30 percent. Such a change increases diarrhea incidence by 35-40 percent.
3) Santosh forwarded me an interesting study by Abhijit Banerjee, Esther Duflo, and Rachel Glennerster, about an experimental intervention run amok in India. I wasn't able to find a link for this, but I will post the abstract here. The basic message? Existing governing and administration structures need to be brought into the intervention decision and implementation
process before they become a hindrance. If the stake-holders aren't participating (or are indifferent), you've got an uphill task.
The Indian Health Care system is plagued by high staff absence; low effort by the providers; and limited use by potential beneficiaries, who prefer private alternatives. This paper reports the results of an experiment carried out with a district administration and a nongovernmental organization (NGO). The presence of government nurses in government public health facilities (sub-centers and aid-posts) was recorded by the NGO, and the government took steps to punish the worst delinquents. Initially, the monitoring system was extremely effective. This shows that nurses are responsive to financial incentives. But after a few months, the local health administration appears to have undermined the scheme from the inside, by letting the nurses claim an increasing number of “exempt days.” Eighteen months after its inception, the program had become completely ineffective.
Friday, November 2, 2007
A Small Window...
...into why I love econ.
Check out this excerpt from a recent post on the Freakonomics blog:
Then, of course, there’s the matter of satisfaction derived from the money itself. Just as a beautiful woman could be described as a “depreciating asset,” so could a rent-free apartment with an unlimited shopping budget. A platinum card may thrill for a few months, but, particularly given the required tradeoff of supplying sexual favors to a man who describes himself as “Danny De Vito with a nicer suit,” it’s also likely to offer diminishing returns.
This Marginal Revolution post about the value of a sports agent is pretty good too.
Both are excellent examples of economic intuition applied to everyday events. I think there are two lessons that come from this. The first is to never underestimate the power of a disciplinary lens. Economics is a powerful method, and allows for systematic analysis into a range of phenomena. The second is to be wary of the danger of going all narrow: sometimes there are insights to be gained from other perspectives. This isn't to say that we should all be jacks-of-trades - I'm a big believer in comparative advantage and returns to specialization. Rather, I think its useful to know the contributions and limits of any one approach, and know where other approaches might fill in any existing gaps.
Check out this excerpt from a recent post on the Freakonomics blog:
Then, of course, there’s the matter of satisfaction derived from the money itself. Just as a beautiful woman could be described as a “depreciating asset,” so could a rent-free apartment with an unlimited shopping budget. A platinum card may thrill for a few months, but, particularly given the required tradeoff of supplying sexual favors to a man who describes himself as “Danny De Vito with a nicer suit,” it’s also likely to offer diminishing returns.
This Marginal Revolution post about the value of a sports agent is pretty good too.
Both are excellent examples of economic intuition applied to everyday events. I think there are two lessons that come from this. The first is to never underestimate the power of a disciplinary lens. Economics is a powerful method, and allows for systematic analysis into a range of phenomena. The second is to be wary of the danger of going all narrow: sometimes there are insights to be gained from other perspectives. This isn't to say that we should all be jacks-of-trades - I'm a big believer in comparative advantage and returns to specialization. Rather, I think its useful to know the contributions and limits of any one approach, and know where other approaches might fill in any existing gaps.
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