This is the meta-subject of a new paper in PLoS ONE by myself and my buddy/co-author Brendan Maughan Brown. Here is the abstract, which mostly explains everything:
Objectives
We examined whether knowledge of the HIV-protective benefits of male circumcision (MC) led to risk compensating behavior in a traditionally circumcising population in South Africa. We extend the current literature by examining risk compensation among women, which has hitherto been unexplored.
Methods
We used data on Xhosa men and women from the 2009 Cape Area Panel Study. Respondents were asked if they had heard that MC reduces a man’s risk of contracting HIV, about their perceived risk of contracting HIV, and condom use. For each gender group we assessed whether risk perception and condom use differed by knowledge of the protective benefits of MC using bivariate and then multivariate models controlling for demographic characteristics, HIV knowledge/beliefs, and previous sexual behaviors. In a further check for confounding, we used data from the 2005 wave to assess whether individuals who would eventually become informed about the protective benefits of circumcision were already different in terms of HIV risk perception and condom use.
Results
34% of men (n = 453) and 27% of women (n = 690) had heard that circumcision reduces a man’s risk of HIV infection. Informed men perceived slightly higher risk of contracting HIV and were more likely to use condoms at last sex (p<0.10). Informed women perceived lower HIV risk (p<0.05), were less likely to use condoms both at last sex (p<0.10) and more generally (p<0.01), and more likely to forego condoms with partners of positive or unknown serostatus (p<0.01). The results were robust to covariate adjustment, excluding people living with HIV, and accounting for risk perceptions and condom use in 2005.
Basically, our results show that women react to information on circumcision's protective benefits in a manner consistent with risk compensation, which is a phenomenon where individuals undertake risky behaviors if they feel that they are protected from its consequences somehow. Why do women respond differently from men? We aren't sure, but we theorize that it could be related to (some combination of):
-Misinformation among women about the protective benefits of circumcision as far as male-to-female HIV transmission (circumcision has only been shown to impact female-to-male transmission).
-Lack of opportunities for women to discuss circumcision, sex, and HIV in public places.
-Higher prior probabilities of contract HIV in women (which means risk information will be more likely to shift beliefs about HIV on the margin - good ole' Bayes's Theorem)
-A sense of reduced need among women to have to negotiate condoms, which could be tricky in a world where there is imbalance in power across genders.
Some new research by other groups (more on this in a later post) provides evidence that the first of these could be at play. Watch this space for more, as we attempt to find some explanations!
Showing posts with label economics. Show all posts
Showing posts with label economics. Show all posts
Friday, August 10, 2012
Thursday, July 26, 2012
Does Expanding Medicaid Save Lives?
According to this recent paper by Ben Sommers, et al, in The New England Journal of Medicine, the answer is yes. Sommers and coauthors examine mortality before and after medicaid expansions in certain states, using the same before-after comparison in neighboring states as a control to account for general trends in mortality that would exist without Medicaid changes. They find expansions "were associated with a significant reduction in adjusted all-cause mortality (by 19.6 deaths per 100,000 adults, for a relative reduction of 6.1%; P=0.001)...Mortality reductions were greatest among older adults, nonwhites, and residents of poorer counties." They also find evidence of better self-reported health and reduced delays to getting care with Medicaid expansions.
This is a well done, timely piece. The recent Supreme Court ruling declared the provisions in the Affordable Care Act (ACA) decreeing mandatory Medicaid expansions to be unconstitutional. This has led some state governors to announce that they will not pursue such expansions. Some of this, of course, is dumb election year posturing: the ACA increases the Federal fund matching rate for Medicaid by a great deal, so governors will most likely buy in to the expansions because of these nice financial incentives. That said, this piece provides another angle to this whole debate, as failure to expand Medicaid may not just mean money left on the table, but people's lives as well.
This is a well done, timely piece. The recent Supreme Court ruling declared the provisions in the Affordable Care Act (ACA) decreeing mandatory Medicaid expansions to be unconstitutional. This has led some state governors to announce that they will not pursue such expansions. Some of this, of course, is dumb election year posturing: the ACA increases the Federal fund matching rate for Medicaid by a great deal, so governors will most likely buy in to the expansions because of these nice financial incentives. That said, this piece provides another angle to this whole debate, as failure to expand Medicaid may not just mean money left on the table, but people's lives as well.
Wednesday, July 18, 2012
Value Based Puchasing and Safety Net Hospitals
One of the mainstays of our current health care reform dialogue is promoting efficiency. The US health care system gets pretty good outcomes for its clients, but it comes at a great cost and with a lack of equity. Regarding cost, there has been a push to pay providers (doctors, clinics, hospitals, etc) for the quality of the services they render, not just for having rendered the service. Along these lines, with the new health care reform bill, Medicare will start paying hospitals based on performance as measured by the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS). This is what is referred to as Value Based Purchasing (VBP).
En face, it sounds like a great idea. But are there potential downsides to VBP? An elegant new study by Paula Chatterjee and colleagues suggests that the answer might be yes. Paula, et al, look at how safety net hospitals, a group of providers that disproptionately take care of poor, vulnerable patients have performed on HCAHPS surveys, showing that these hospitals typically have fared work on the patient satisfaction aspect of this index. Strikingly, safety net hospitalis were 60% less likely to be at or above the median on a variety of patient experience measures when compared to other hospitals. Because the median is the key metric upon which the Medicare VBP algorithms are based, safety net hospitals will potentially stand to lose key Medicare dollars. As they are financially constrained as it is, this could potentially lead to a negative feedback loop, where safety net hospitals lack the funds to make the improvements necessary to perform better on VBP, thereby losing more funds, and so on.
This example highlights a few key points that are relevant for health care reform anywhere. First, certain kinds of incentives will create, or exacerbate existing, tradeoffs between making the system more equitable versus more efficient. In this case, the push for efficiency may potentially reduce available care options for the poor, which leads to worsening equity. Note that this could even lead to worsened efficiency, if the lack of immediate care for the poor leads to increased downstream costs (eg, more ED visits, or longer hospitalizations when an earlier, less costly, hospitalization would have done). Second, better designed incentives may actually help move to an equilibrium where this tradeoff is minimized. For example, a VBP system which allows safety net hospitals lead time in figuring out best practices (perhaps via learning from each other, or via some explicit "curriculum" or forum created by Medicare) may help them improve quality -which will certainly be equitable given their population- and stay solvent.
Ultimately, I think key for payment reform, which should be the explicit goal for Medicare and other health programs, is to perform the reachable alchemy of improving both equity and efficiency. I say "reachable" for a reason: everyone is aware that other OECD countries spend less and gain the same or more when it comes to health. At least on a less fundamental level (i.e, payment reform within our mish-mosh private system), we can aim to do the same.
En face, it sounds like a great idea. But are there potential downsides to VBP? An elegant new study by Paula Chatterjee and colleagues suggests that the answer might be yes. Paula, et al, look at how safety net hospitals, a group of providers that disproptionately take care of poor, vulnerable patients have performed on HCAHPS surveys, showing that these hospitals typically have fared work on the patient satisfaction aspect of this index. Strikingly, safety net hospitalis were 60% less likely to be at or above the median on a variety of patient experience measures when compared to other hospitals. Because the median is the key metric upon which the Medicare VBP algorithms are based, safety net hospitals will potentially stand to lose key Medicare dollars. As they are financially constrained as it is, this could potentially lead to a negative feedback loop, where safety net hospitals lack the funds to make the improvements necessary to perform better on VBP, thereby losing more funds, and so on.
This example highlights a few key points that are relevant for health care reform anywhere. First, certain kinds of incentives will create, or exacerbate existing, tradeoffs between making the system more equitable versus more efficient. In this case, the push for efficiency may potentially reduce available care options for the poor, which leads to worsening equity. Note that this could even lead to worsened efficiency, if the lack of immediate care for the poor leads to increased downstream costs (eg, more ED visits, or longer hospitalizations when an earlier, less costly, hospitalization would have done). Second, better designed incentives may actually help move to an equilibrium where this tradeoff is minimized. For example, a VBP system which allows safety net hospitals lead time in figuring out best practices (perhaps via learning from each other, or via some explicit "curriculum" or forum created by Medicare) may help them improve quality -which will certainly be equitable given their population- and stay solvent.
Ultimately, I think key for payment reform, which should be the explicit goal for Medicare and other health programs, is to perform the reachable alchemy of improving both equity and efficiency. I say "reachable" for a reason: everyone is aware that other OECD countries spend less and gain the same or more when it comes to health. At least on a less fundamental level (i.e, payment reform within our mish-mosh private system), we can aim to do the same.
Sunday, July 15, 2012
PEPFAR on the Mind
The July 31st issue of Health Affairs devotes itself to the President's Emergency Plan for AIDS Relief (PEPFAR) and explores the aid program from a number of interesting viewpoints. The highlights for me includes a piece by Harsha Thirumurthy and coauthors on the economic benefits of treating HIV and a wonderful piece of research by Karen Grepin examining the effects of PEPFAR aid on other domains on health care (she finds positive spillovers for certain maternal health services, but crowd-out for child vaccines). The article by John Donnelly discusses the origin of PEPFAR within the (W) Bush administration, which I am sure would make most send some positive vibes to this otherwise beleaguered president.
The articles on the future of PEPFAR (how the funding streams can be better targeted, how much funding is needed and for how much longer) are quite interesting, as well. Certainly, if you have a particular interest in PEPFAR, the whole issue is worth reading.
The articles on the future of PEPFAR (how the funding streams can be better targeted, how much funding is needed and for how much longer) are quite interesting, as well. Certainly, if you have a particular interest in PEPFAR, the whole issue is worth reading.
Monday, April 16, 2012
Poorly Conceived Incentives in Health Care: The AM Discharge
There's no shortage of examples of well-meaning, but ultimately failing, incentives in health care, but here is a recent one that I've come across as an intern. In the community hospital we all rotate through, interns are paid $5 dollars if they manage to discharge 2 patients by 10 AM. Early discharges are valued by hospitals because they help with turnover and flow: overcrowding in the emergency room is kept to a minimum if hospital beds are available in the morning. But discharges take time: as an intern, we have to round on all of our inpatients in the morning, any new patients we inherit from the overnight team, and write a bunch of orders and notes. Discharges require thought, often irritating paperwork and emails, and all of that crowds out time for these other tasks. Furthermore, discharging people only means that you'll get more new patients later. For most of us, that's usually exciting, but its easy to see how this may seem like a penalty for keeping the hospital's best interests in mind.
In most places I've worked, there are no incentives for residents to get people out by noon, other than to avoid having to be gently reminded (over and over) by case managers and nurses to get the work done. Obviously, since the (opportunity) costs far outweigh the benefits, I'm sure most interns and residents are not in real rush to discharge people when they could being doing other things for their patients (or themselves).
Enter the hospital where I am now. They've ostensibly addressed this incentive compatibility problem by offering a small financial incentive for a certain number of pre-10 AM discharges. However, I think their $5 scheme is doomed to fail for two reasons. First, $5 dollars is not much money and most of us value our time far more than that. Second, and likely worse, such small incentives may actually make us less likely to move people out the door. Indeed, a number of experimental studies in behavioral economics and psychology have shown that small monetary rewards may reduce effort, either by reminding us that we get paid less than our peers in other fields or by demeaning us (or the task) with the size of the offer. Several of the interns I've spoken to have interpreted the incentive scheme in the latter light.
So what is the right kind of incentive? There are several, likely more effective, options. One is to increase the cash value of the incentive: perhaps the intern or resident at the end of the month (or year, to reduce sampling error as far as the medical problems and sickness of the patient) gets $100 or more for getting the most people out by noon. Perhaps even better is to take the monetary aspect out of it, altogether. As physicians, many of us value the altruism that goes with the field. Why not make the hospital brass-resident relationship center around that aspect and reward the intern/resident who discharges most effectively with some kind of public, visible and worthy commendation that he/she is a good doctor (at least one valued by the hospital for his/her attention to patient care and the realities of health care delivery on a larger scale)?
In most places I've worked, there are no incentives for residents to get people out by noon, other than to avoid having to be gently reminded (over and over) by case managers and nurses to get the work done. Obviously, since the (opportunity) costs far outweigh the benefits, I'm sure most interns and residents are not in real rush to discharge people when they could being doing other things for their patients (or themselves).
Enter the hospital where I am now. They've ostensibly addressed this incentive compatibility problem by offering a small financial incentive for a certain number of pre-10 AM discharges. However, I think their $5 scheme is doomed to fail for two reasons. First, $5 dollars is not much money and most of us value our time far more than that. Second, and likely worse, such small incentives may actually make us less likely to move people out the door. Indeed, a number of experimental studies in behavioral economics and psychology have shown that small monetary rewards may reduce effort, either by reminding us that we get paid less than our peers in other fields or by demeaning us (or the task) with the size of the offer. Several of the interns I've spoken to have interpreted the incentive scheme in the latter light.
So what is the right kind of incentive? There are several, likely more effective, options. One is to increase the cash value of the incentive: perhaps the intern or resident at the end of the month (or year, to reduce sampling error as far as the medical problems and sickness of the patient) gets $100 or more for getting the most people out by noon. Perhaps even better is to take the monetary aspect out of it, altogether. As physicians, many of us value the altruism that goes with the field. Why not make the hospital brass-resident relationship center around that aspect and reward the intern/resident who discharges most effectively with some kind of public, visible and worthy commendation that he/she is a good doctor (at least one valued by the hospital for his/her attention to patient care and the realities of health care delivery on a larger scale)?
Saturday, April 14, 2012
Can Tax Breaks Help Decrease Organ Shortages?
Despite advances in organ procurement, immune suppression (to prevent the body from rejecting a transplant), and surgical techniques, organ shortages and wait list numbers continue to grow in the United States. Calls for instituting organ markets (including ones from prominent economists) notwithstanding, ethical concerns have made outright payments for organs a non-starter policy in the American context. However, policymakers have recognized that those who wish to donate organs, particularly living donors, may face enormous costs in the form of lost wages, health care costs and travel and lodging fees. As such, efforts have been made to reduce these financial barriers to donation: in the last decade, 16 states have now passed laws to provide tax deductions to living organ donors, with many other considering similar legislation.
Have these policies been effective in increasing donation rates? In a new paper in the American Journal of Transplantation, Erika Martin, Anitha Vijayan, Jason Wellen and I explore this question using data on living organ donations and transplants for each state between 2000-2010. Our research design basically compares the change in donation rates before and after the enactment of a tax policy in states that passed these laws against the change in same time period in those states that did not (the differences-in-differences design). We found no evidence that these laws were effective in appreciably closing the organ shortage. At most, they may have led to 5% increases in donation rates (the upper bound of our confidence intervals) - not too bad, but not the panacea.
Why is this the case? First off, tax deductions don't put that much money back in your pocket. For an upper middle class family of four, the value of a deduction amounts to $500-$900. Nothing to sneer at, but still below the estimated (opportunity) cost of making a donation. We argue that tax credits (which have a higher cash value) or grants may work better. Second, in doing the research we ended up talking to organ donation activists in many states, many of whom had no idea these policies were in place! It's possible that a lack of awareness led to our null finding, as well. Finally, while we don't elaborate on this in the paper, our Figure 1 shows that states that passed these laws experienced increasing donation rates relative to the other set of states prior to the passage of the laws. So it's possible that states that were progressive enough to pass tax deductions were already doing other things to bump up donation rates.
Finally, while tax deductions may not lead to new donors, they may be helping people who would donate anyway. For example, a living donor who is compensated for his/her private costs because of the tax policy, perhaps as a result in less financial distress, certainly would benefit from the policy. We don't really have the data to examine this "intensive margin." On this point, I wouldn't yet write tax policies off.
Have these policies been effective in increasing donation rates? In a new paper in the American Journal of Transplantation, Erika Martin, Anitha Vijayan, Jason Wellen and I explore this question using data on living organ donations and transplants for each state between 2000-2010. Our research design basically compares the change in donation rates before and after the enactment of a tax policy in states that passed these laws against the change in same time period in those states that did not (the differences-in-differences design). We found no evidence that these laws were effective in appreciably closing the organ shortage. At most, they may have led to 5% increases in donation rates (the upper bound of our confidence intervals) - not too bad, but not the panacea.
Why is this the case? First off, tax deductions don't put that much money back in your pocket. For an upper middle class family of four, the value of a deduction amounts to $500-$900. Nothing to sneer at, but still below the estimated (opportunity) cost of making a donation. We argue that tax credits (which have a higher cash value) or grants may work better. Second, in doing the research we ended up talking to organ donation activists in many states, many of whom had no idea these policies were in place! It's possible that a lack of awareness led to our null finding, as well. Finally, while we don't elaborate on this in the paper, our Figure 1 shows that states that passed these laws experienced increasing donation rates relative to the other set of states prior to the passage of the laws. So it's possible that states that were progressive enough to pass tax deductions were already doing other things to bump up donation rates.
Finally, while tax deductions may not lead to new donors, they may be helping people who would donate anyway. For example, a living donor who is compensated for his/her private costs because of the tax policy, perhaps as a result in less financial distress, certainly would benefit from the policy. We don't really have the data to examine this "intensive margin." On this point, I wouldn't yet write tax policies off.
Monday, March 26, 2012
Dear Rush Limbaugh: Oral Contraceptives Have Positive Labor Market Consequences!
Rush Limbaugh doesn't like oral contraception. At least, he doesn't think health insurers should have to pay it ('Dar He Blogs will keep this debate academic and avoid any "pot-kettle-black" type comments). I'm guessing he wasn't aware of a new study by Martha Bailey and co-authors illustrating the large, positive labor market effects "The Pill" has provided for women:
Decades of research on the U.S. gender gap in wages describes its correlates, but little is known about why women changed their career paths in the 1960s and 1970s. This paper explores the role of “the Pill” in altering women’s human capital investments and its ultimate implications for life-cycle wages. Using state-by-birth-cohort variation in legal access to contraception, we show that younger access to the Pill conferred an 8-percent hourly wage premium by age fifty. Our estimates imply that the Pill can account for 10 percent of the convergence of the gender gap in the 1980s and 30 percent in the 1990s.
Why would birth control pills enable women to earn more? By allowing more control over the reproductive cycle, this would reduce uncertainty in the timing of certain events, such as pursuing college, job training opportunities, and entering the workforce. One could easily imagine how providing women with relative certainty could lead to more investment in their "human capital" because it is now easier to do so and the returns become more predictable.
Another way oral contraceptives can help in the labor market has to do with absenteeism due to menstruation. In a really neat study, Andrea Ichino and Enrico Moretti show that work absences for young women follow a 28 day cycle, whereas those for women over the age of 45, and men of any age, do not. They suggest that this pattern is due to menstruation and go on to calculate that lost work days on the account of the cycle may explain 14% of the gender differential in earnings seen in their Italian dataset.
Decades of research on the U.S. gender gap in wages describes its correlates, but little is known about why women changed their career paths in the 1960s and 1970s. This paper explores the role of “the Pill” in altering women’s human capital investments and its ultimate implications for life-cycle wages. Using state-by-birth-cohort variation in legal access to contraception, we show that younger access to the Pill conferred an 8-percent hourly wage premium by age fifty. Our estimates imply that the Pill can account for 10 percent of the convergence of the gender gap in the 1980s and 30 percent in the 1990s.
Why would birth control pills enable women to earn more? By allowing more control over the reproductive cycle, this would reduce uncertainty in the timing of certain events, such as pursuing college, job training opportunities, and entering the workforce. One could easily imagine how providing women with relative certainty could lead to more investment in their "human capital" because it is now easier to do so and the returns become more predictable.
Another way oral contraceptives can help in the labor market has to do with absenteeism due to menstruation. In a really neat study, Andrea Ichino and Enrico Moretti show that work absences for young women follow a 28 day cycle, whereas those for women over the age of 45, and men of any age, do not. They suggest that this pattern is due to menstruation and go on to calculate that lost work days on the account of the cycle may explain 14% of the gender differential in earnings seen in their Italian dataset.
Thursday, March 22, 2012
Shortening Medical Training? Yes, Please!
Those who want to become a doctor in the United States stare at a very long road: 4 years of college, 4 years of medical school, 3-7 years of residency and, potentially, fellowship to finish it all off. (Some crazies additionally tack on another 1-5 years to do this in pursuing a joint degree, as well). But does it really require all this time to create a doctor well-equipped to fight disease in our current times?
None another than Ezekiel Emanuel and Victor Fuchs (one of the Founding Fathers of health economics) think that the answer is "no." In a recent piece in the Journal of the American Medical Association, they state that the current educational system for physicians is, in fact, wasteful. They point out that a physician today cannot credibly be the superhero, one-man-band of master clinician, penetrating researcher, community pillar, and public intellectual that she/he was expected to be up through the 1980s. The state that the complexity of medicine today requires a team based approach where doctors are relative specialists. Emanuel and Fuchs illustrate how physicians today are now more likely to take on the one (or two) of these archetypical roles that fit with their comparative strengths while letting other members of the larger team fulfill the other roles. In contrast to this new reality of medicine, our current system of medical education is wasteful because it still aims to produce one-man-band types.
So how can medical education be shortened? Emanuel and Fuchs suggest the following:
-Loosen requirements that undergraduate degrees be mandatory (there are plenty of six or seven year combined undergrad-MD programs that produce equally good doctors)
-Cut the pre-clinical years of medical school from 2 to 1.5 years (UPenn and Duke have shortened versions of the classroom years)
-Cut the clinical years from 24 to 15 months (Harvard is currently doing this, quite successfully I might add)
-Eliminate research requirements in residency and fellowship for those who do not want to do them (this, for example, would shave off 2 of the 7 years to become a general surgeon)
-Eliminate "leadership years" (for example, in internal medicine, the third year is to lead teams and has little value added in the education production function)
I am 100% behind this. Much of our current system persists because of historical considerations from nearly a century ago. In the same way that some of our antiquated mechanisms to finance health care (for example, employer sponsored health insurance) don't make much sense anymore, neither does making people spend a great deal of time in training where up to a third of it has little marginal benefit in turning people into good doctors.
If we are concerned with cost and efficiency in the health care system, we ought to paying as much attention to being efficient in how we train doctors as we are in figuring out how to pay them.
None another than Ezekiel Emanuel and Victor Fuchs (one of the Founding Fathers of health economics) think that the answer is "no." In a recent piece in the Journal of the American Medical Association, they state that the current educational system for physicians is, in fact, wasteful. They point out that a physician today cannot credibly be the superhero, one-man-band of master clinician, penetrating researcher, community pillar, and public intellectual that she/he was expected to be up through the 1980s. The state that the complexity of medicine today requires a team based approach where doctors are relative specialists. Emanuel and Fuchs illustrate how physicians today are now more likely to take on the one (or two) of these archetypical roles that fit with their comparative strengths while letting other members of the larger team fulfill the other roles. In contrast to this new reality of medicine, our current system of medical education is wasteful because it still aims to produce one-man-band types.
So how can medical education be shortened? Emanuel and Fuchs suggest the following:
-Loosen requirements that undergraduate degrees be mandatory (there are plenty of six or seven year combined undergrad-MD programs that produce equally good doctors)
-Cut the pre-clinical years of medical school from 2 to 1.5 years (UPenn and Duke have shortened versions of the classroom years)
-Cut the clinical years from 24 to 15 months (Harvard is currently doing this, quite successfully I might add)
-Eliminate research requirements in residency and fellowship for those who do not want to do them (this, for example, would shave off 2 of the 7 years to become a general surgeon)
-Eliminate "leadership years" (for example, in internal medicine, the third year is to lead teams and has little value added in the education production function)
I am 100% behind this. Much of our current system persists because of historical considerations from nearly a century ago. In the same way that some of our antiquated mechanisms to finance health care (for example, employer sponsored health insurance) don't make much sense anymore, neither does making people spend a great deal of time in training where up to a third of it has little marginal benefit in turning people into good doctors.
If we are concerned with cost and efficiency in the health care system, we ought to paying as much attention to being efficient in how we train doctors as we are in figuring out how to pay them.
Saturday, March 3, 2012
Preventing HIV and STDs with Cash Transfers - Both Abroad and Here?
So on the heels of my post a few days ago comes a brand new study in The Lancet where women in Malawi randomized to receive unconditional cash transfers were less likely to contract HIV or other STDs than their unpaid counterparts. Here is a very nice summary piece on the study.
The mechanism linking cash transfers to reduced HIV may have something to do with the fact that women with access to such resources need not depend on men for the same. That is, women who are cash strapped or who lack opportunities in the labor market may need to depend on relationships where the partner can support them financially. Financial support, in turn, may reduce their ability to negotiate safe sex practices (this is the so-called "transactional sex").
Cash transfer programs of this nature may not just be useful overseas. A forthcoming article in the Journal of Adolescent Health shows that young African American women in Atlanta who have boyfriends who give them gifts are less likely to use condoms than those without such boyfriends or those with boyfriends who go on to find another source of spending money. The authors conclude that "receiving spending money from a boyfriend is common among adolescent women in populations targeted by pregnancy and sexually transmitted infection prevention interventions, and may undermine interventions' effectiveness." (HT: Paula C for the Atlanta paper).
The mechanism linking cash transfers to reduced HIV may have something to do with the fact that women with access to such resources need not depend on men for the same. That is, women who are cash strapped or who lack opportunities in the labor market may need to depend on relationships where the partner can support them financially. Financial support, in turn, may reduce their ability to negotiate safe sex practices (this is the so-called "transactional sex").
Cash transfer programs of this nature may not just be useful overseas. A forthcoming article in the Journal of Adolescent Health shows that young African American women in Atlanta who have boyfriends who give them gifts are less likely to use condoms than those without such boyfriends or those with boyfriends who go on to find another source of spending money. The authors conclude that "receiving spending money from a boyfriend is common among adolescent women in populations targeted by pregnancy and sexually transmitted infection prevention interventions, and may undermine interventions' effectiveness." (HT: Paula C for the Atlanta paper).
Friday, March 2, 2012
Aspirations and Investing in Girls
Two great posts in Development Impact (my favorite economics blog right now) on aspirations, expected returns to investments, and the advancement of women. The first reviews evidence on how increased labor market opportunities available to women lead parents to invest more in the daughter's education. The second looks at how recent quotas decreeing that a randomly chosen 1/3 of village governance seats in India be filled by women have led to increased aspirations among girls and their parents, as well as increased investments in the former. In the study they cite, the gender gap in child education (which favors boys at baseline) was decimated when a village headship was randomly assigned to a woman.
The posts, and the articles cited there in, make two powerful points. First, information on opportunities for girls that may be unknown to families (for whom the cost of obtaining such information is high because of, say, lack of access to "plugged in" social networks, media, etc) can be powerful in combating gender bias. Second, proactively breaking down institutional barriers can play an important role, too, something we saw with the Civil Rights Movement here on our shores.
The posts, and the articles cited there in, make two powerful points. First, information on opportunities for girls that may be unknown to families (for whom the cost of obtaining such information is high because of, say, lack of access to "plugged in" social networks, media, etc) can be powerful in combating gender bias. Second, proactively breaking down institutional barriers can play an important role, too, something we saw with the Civil Rights Movement here on our shores.
Monday, February 27, 2012
Preventing HIV By Paying People to Maintain Safe Sex Practices
Finding an HIV prevention strategy that works is one of the Holy Grail's of public health policy. Indeed, poor evidence of the epidemic quelling effects of most prevention programs (outside of biomedical interventions such as circumcision) have driven many to accept that treatment may actually be the best preventive device we have.
That may be true, but I do not think that all modes of prevention have been exhausted. One margin where there is some growing evidence is in providing cash transfers for people who maintain a given set of behaviors over a period of time. For example, one could pay people for every month they do not test positive for HIV. Such methods have been tried in the substance abuse world, apparently to good effect. Could it work with HIV/AIDS?
In a great new NBER working paper, Damien de Walque, William H. Dow, Carol Medlin, and Rose Nathan argue that the answer is a resounding yes (ungated version here). From the abstract:
[W]e discuss the use of sexual-behavior incentives in the Tanzanian RESPECT trial. There, participants who tested negative for sexually transmitted infections are eligible for outcome-based cash rewards. The trial was well-received in the communities, with high enrollment rates and over 90% of participants viewing the incentives favorably. After one year, 57% of enrollees in the “low-value” reward arm stated that the cash rewards “very much” motivated sexual behavioral change, rising to 79% in the “high-value” reward arm. Despite its controversial nature, we argue for further testing of such incentive-based approaches to encouraging reductions in risky sexual behavior.
The abstract undersells some of the evidence they cite in the paper, so I would go ahead and read the entire thing. While people may somehow find it reprehensible to pay people to do the right thing, there is already a great precedent in education and yearly doctor visits (i.e., conditional cash transfers for those things are all the rage in the Americas) as well as (as mentioned above) with getting people to stop using illicit/recreational drugs.
That may be true, but I do not think that all modes of prevention have been exhausted. One margin where there is some growing evidence is in providing cash transfers for people who maintain a given set of behaviors over a period of time. For example, one could pay people for every month they do not test positive for HIV. Such methods have been tried in the substance abuse world, apparently to good effect. Could it work with HIV/AIDS?
In a great new NBER working paper, Damien de Walque, William H. Dow, Carol Medlin, and Rose Nathan argue that the answer is a resounding yes (ungated version here). From the abstract:
[W]e discuss the use of sexual-behavior incentives in the Tanzanian RESPECT trial. There, participants who tested negative for sexually transmitted infections are eligible for outcome-based cash rewards. The trial was well-received in the communities, with high enrollment rates and over 90% of participants viewing the incentives favorably. After one year, 57% of enrollees in the “low-value” reward arm stated that the cash rewards “very much” motivated sexual behavioral change, rising to 79% in the “high-value” reward arm. Despite its controversial nature, we argue for further testing of such incentive-based approaches to encouraging reductions in risky sexual behavior.
The abstract undersells some of the evidence they cite in the paper, so I would go ahead and read the entire thing. While people may somehow find it reprehensible to pay people to do the right thing, there is already a great precedent in education and yearly doctor visits (i.e., conditional cash transfers for those things are all the rage in the Americas) as well as (as mentioned above) with getting people to stop using illicit/recreational drugs.
Monday, February 6, 2012
Does Discrimination Make You Sick? And How?
Interesting new paper, forthcoming in the Journal of Health Economics, that uses 9/11 as a quasi-experimental source of variation to try and get at the causal effect of discrimination (here, against Muslims in the UK) on health outcomes. It also goes a bit further than this and tries to get at some of the mechanisms. The findings are, sadly, along the lines of what I expected:
The attitudes of the general British population towards Muslims changed post 2001, and this change led to a significant increase in Anti-Muslim discrimination. We use this exogenous attitude change to estimate the causal impact of increased discrimination on a range of objective and subjective health outcomes. The difference-in-differences estimates indicate that discrimination worsens blood pressure, cholesterol, BMI and self-assessed general health. Thus, discrimination is a potentially important determinant of the large racial and ethnic health gaps observed in many countries. We also investigate the pathways through which discrimination impacts upon health, and find that discrimination has a negative effect on employment, perceived social support, and health-producing behaviours. Crucially, our results hold for different control groups and model specifications.
So in addition to the deadweight loss of underutilizing potentially talented men and women, as well as increasing social unrest and the potential political costs that might have, we can now add health to the slew of negative impacts from discrimination.
In a later post, I'll go over a paper that Sonia Bhalotra and I are working on that looks at how discrimination can prevent children who have better childhoods into tapping into that wellspring as adults.
The attitudes of the general British population towards Muslims changed post 2001, and this change led to a significant increase in Anti-Muslim discrimination. We use this exogenous attitude change to estimate the causal impact of increased discrimination on a range of objective and subjective health outcomes. The difference-in-differences estimates indicate that discrimination worsens blood pressure, cholesterol, BMI and self-assessed general health. Thus, discrimination is a potentially important determinant of the large racial and ethnic health gaps observed in many countries. We also investigate the pathways through which discrimination impacts upon health, and find that discrimination has a negative effect on employment, perceived social support, and health-producing behaviours. Crucially, our results hold for different control groups and model specifications.
So in addition to the deadweight loss of underutilizing potentially talented men and women, as well as increasing social unrest and the potential political costs that might have, we can now add health to the slew of negative impacts from discrimination.
In a later post, I'll go over a paper that Sonia Bhalotra and I are working on that looks at how discrimination can prevent children who have better childhoods into tapping into that wellspring as adults.
Saturday, February 4, 2012
Public Health and Health Care Reform
As the fate of the Affordable Care Act (ACA) hangs in the balance, the Obama administration has had to make some compromises in order to keep the bill afloat. One of these is cutting #3.5 billion from the $15 billion Prevention and Public Health Fund. The fund exists given increasing recognition that a majority of chronic disease we see now are likely secondary to what are public health issues (changing diets, limited opportunities to exercise, pollution, etc).
The usual justification for public health is that, in the long-run, it prevents disease and thereby lowers health care costs. I think this is fundamentally correct. However, it's a tired argument, especially in the context of four-year political cycles (why wait on cost savings that will take a long time to materialize if they don't confer any immediate electoral benefit?) and a natural fixation over observable events (it's hard to appreciate things that don't happen, but seeing someone catheterize an occluding blood vessel to the heart is real and amazing; doing something about that raises political visibility).
Enter Nicholas Stine and Dave Chokshi, both physicians at the Brigham and Women's Hospital. They have a nice perspective piece in this week's New England Journal of Medicine that makes a fresh case for public health expenditures. In particular, they cleverly frame the value of public health in terms of immediate cost savings and current cost-control objectives in health care. Some of the more interesting points:
-We are now interested in paying for good quality health services rather than health services in general. There is also a push to think more about population management? Which means we need to be able to measure things we've never measured before on a larger scale. Public health organizations have the know-how and capacity to do population surveillance which can be helpful in this regard. Why not outsource the data gathering and analysis aspects for both quality, capacity and population based outcome measures to the pros? In this way, spending on public health will have spillovers to the medical care.
-More generally, we can use public health departments help organize IT. It is now very difficult for smaller practices or hospitals to afford good IT. Outsourcing this to a larger organzation that could perhaps manage IT for many different providers could be really useful in cutting costs for individual firms both in the short and long-run.
-In the same way we are paying for good health care, why not introduce financial incentives for good public health, so as to glean gains from it in the shorter run?
This is a great piece because it takes the public health versus medicine issue and illustrates how the two are complementary. The new angle is that the complementarities can lead to cost-savings sooner than we'd expect, and can help augment and empower current initiatives on the medical care side to improve quality and cut costs. Even their title is beautiful: I'm sure that "Opportunity in Austerity" is what every politician wants to hear now!
The usual justification for public health is that, in the long-run, it prevents disease and thereby lowers health care costs. I think this is fundamentally correct. However, it's a tired argument, especially in the context of four-year political cycles (why wait on cost savings that will take a long time to materialize if they don't confer any immediate electoral benefit?) and a natural fixation over observable events (it's hard to appreciate things that don't happen, but seeing someone catheterize an occluding blood vessel to the heart is real and amazing; doing something about that raises political visibility).
Enter Nicholas Stine and Dave Chokshi, both physicians at the Brigham and Women's Hospital. They have a nice perspective piece in this week's New England Journal of Medicine that makes a fresh case for public health expenditures. In particular, they cleverly frame the value of public health in terms of immediate cost savings and current cost-control objectives in health care. Some of the more interesting points:
-We are now interested in paying for good quality health services rather than health services in general. There is also a push to think more about population management? Which means we need to be able to measure things we've never measured before on a larger scale. Public health organizations have the know-how and capacity to do population surveillance which can be helpful in this regard. Why not outsource the data gathering and analysis aspects for both quality, capacity and population based outcome measures to the pros? In this way, spending on public health will have spillovers to the medical care.
-More generally, we can use public health departments help organize IT. It is now very difficult for smaller practices or hospitals to afford good IT. Outsourcing this to a larger organzation that could perhaps manage IT for many different providers could be really useful in cutting costs for individual firms both in the short and long-run.
-In the same way we are paying for good health care, why not introduce financial incentives for good public health, so as to glean gains from it in the shorter run?
This is a great piece because it takes the public health versus medicine issue and illustrates how the two are complementary. The new angle is that the complementarities can lead to cost-savings sooner than we'd expect, and can help augment and empower current initiatives on the medical care side to improve quality and cut costs. Even their title is beautiful: I'm sure that "Opportunity in Austerity" is what every politician wants to hear now!
Sunday, January 29, 2012
Random Links: Read "Short White Coat," the Value of a Good Kindergarten Experience, and Why Drop Out?
My co-intern in the primary care program, Ishani Ganguli, is an incredibly thoughtful individual who writes really well. She has a blog (a real blog, one with a consistently large readership that is fronted by the Boston Globe) that discusses various aspects of health care and medical education through the eyes of a resident. Worth checking out, especially her latest post on teamwork in health care.
-There's a great book, now a classic, by Robert Fulgham called "All I Really Need to Know I Learned in Kindergarten." Now some new research from some big shot economists on the value of a good kindergarten experience:
In Project STAR, 11,571 students in Tennessee and their teachers were randomly assigned to classrooms within their schools from kindergarten to third grade. This paper evaluates the long-term impacts of STAR by linking the experimental data to administrative records. We first demonstrate that kindergarten test scores are highly correlated with outcomes such as earnings at age 27, college attendance, home ownership, and retirement savings. We then document four sets of experimental impacts. First, students in small classes are significantly more likely to attend college and exhibit improvements on other outcomes. Class size does not have a significant effect on earnings at age 27, but this effect is imprecisely estimated. Second, students who had a more experienced teacher in kindergarten have higher earnings. Third, an analysis of variance reveals significant classroom effects on earnings. Students who were randomly assigned to higher quality classrooms in grades K-3 – as measured by classmates' end-of-class test scores – have higher earnings, college attendance rates, and other outcomes. Finally, the effects of class quality fade out on test scores in later grades but gains in non-cognitive measures persist.
-In related news, there's a great recent NYT Op-Ed on the cost of high school dropouts to the US economy (thanks James Hudspeth!). The authors (both well known economists) mention the following:
Studies show that the typical high school graduate will obtain higher employment and earnings — an astonishing 50 percent to 100 percent increase in lifetime income — and will be less likely to draw on public money for health care and welfare and less likely to be involved in the criminal justice system.
So a good economics question: if high school completion is so valuable, why would anyone drop out? Is it because of ability (low ability kids are forced out), time preference (the value of now exceeds the returns of income later?), or a lack of information about the returns to high school? There are other explanations. But if we assume that people make choices based on marginal returns, it seems bizarre that so many would drop out and leave that kind of money on the table, right? Thoughts?
-There's a great book, now a classic, by Robert Fulgham called "All I Really Need to Know I Learned in Kindergarten." Now some new research from some big shot economists on the value of a good kindergarten experience:
In Project STAR, 11,571 students in Tennessee and their teachers were randomly assigned to classrooms within their schools from kindergarten to third grade. This paper evaluates the long-term impacts of STAR by linking the experimental data to administrative records. We first demonstrate that kindergarten test scores are highly correlated with outcomes such as earnings at age 27, college attendance, home ownership, and retirement savings. We then document four sets of experimental impacts. First, students in small classes are significantly more likely to attend college and exhibit improvements on other outcomes. Class size does not have a significant effect on earnings at age 27, but this effect is imprecisely estimated. Second, students who had a more experienced teacher in kindergarten have higher earnings. Third, an analysis of variance reveals significant classroom effects on earnings. Students who were randomly assigned to higher quality classrooms in grades K-3 – as measured by classmates' end-of-class test scores – have higher earnings, college attendance rates, and other outcomes. Finally, the effects of class quality fade out on test scores in later grades but gains in non-cognitive measures persist.
-In related news, there's a great recent NYT Op-Ed on the cost of high school dropouts to the US economy (thanks James Hudspeth!). The authors (both well known economists) mention the following:
Studies show that the typical high school graduate will obtain higher employment and earnings — an astonishing 50 percent to 100 percent increase in lifetime income — and will be less likely to draw on public money for health care and welfare and less likely to be involved in the criminal justice system.
So a good economics question: if high school completion is so valuable, why would anyone drop out? Is it because of ability (low ability kids are forced out), time preference (the value of now exceeds the returns of income later?), or a lack of information about the returns to high school? There are other explanations. But if we assume that people make choices based on marginal returns, it seems bizarre that so many would drop out and leave that kind of money on the table, right? Thoughts?
Friday, January 27, 2012
Partisan Professors and Race
Great new paper in the latest issue of the American Economic Journal: Applied Economics about the political orientation of your professor and the grade you may receive in her/his class:
We study grading outcomes associated with professors in an elite university in the United States who were identified—using voter registration records from the county where the university is located—as either Republicans or Democrats. The evidence suggests that student grades are linked to the political orientation of professors. Relative to their Democratic colleagues, Republican professors are associated with a less egalitarian distribution of grades and with lower grades awarded to black students relative to whites.
The paper is by Bar and Zussman and their models look at variations in grades within the same student taking courses in the same department, so it controls for selection into majors and, to some extent, classes. The most interesting part of this paper is the race angle. One may think that it has something to do with the fact the demographics of Republican professors, not so much their ideological preferences. Not so: even controlling for gender, age and race of the professor doesn't change the results.
So how to interpret this? I'm sure that many would argue that Republican professors harbor some subtle, perhaps subconscious, prejudices against black students (this guy would agree). This is entirely possible, but I think the study needs to be interpreted with some caution. First, the sample size of Republican professors is small (only 5.3% are). Secondly, its unclear where the grade variation is coming from. Do students - black or white - perform worse in Republican-professor taught classes (they don't like the take on the material, they may be too ticked off with partisan politics to focus on assignments, etc)? The study can't distinguish this explanation from the racist-professor one.
We study grading outcomes associated with professors in an elite university in the United States who were identified—using voter registration records from the county where the university is located—as either Republicans or Democrats. The evidence suggests that student grades are linked to the political orientation of professors. Relative to their Democratic colleagues, Republican professors are associated with a less egalitarian distribution of grades and with lower grades awarded to black students relative to whites.
The paper is by Bar and Zussman and their models look at variations in grades within the same student taking courses in the same department, so it controls for selection into majors and, to some extent, classes. The most interesting part of this paper is the race angle. One may think that it has something to do with the fact the demographics of Republican professors, not so much their ideological preferences. Not so: even controlling for gender, age and race of the professor doesn't change the results.
So how to interpret this? I'm sure that many would argue that Republican professors harbor some subtle, perhaps subconscious, prejudices against black students (this guy would agree). This is entirely possible, but I think the study needs to be interpreted with some caution. First, the sample size of Republican professors is small (only 5.3% are). Secondly, its unclear where the grade variation is coming from. Do students - black or white - perform worse in Republican-professor taught classes (they don't like the take on the material, they may be too ticked off with partisan politics to focus on assignments, etc)? The study can't distinguish this explanation from the racist-professor one.
Wednesday, December 14, 2011
Health Expenditures in the US: Are We Not Spending Enough?
According the Elizabeth Bradley, a Professor of Health Policy and Administration at Yale, the answer is no. As she and Lauren Taylor point out in a recent New York Times editorial:
We studied 10 years’ worth of data and found that if you counted the combined investment in health care and social services, the United States no longer spent the most money — far from it. In 2005, for example, the United States devoted only 29 percent of gross domestic product to health and social services combined, while countries like Sweden, France, the Netherlands, Belgium and Denmark dedicated 33 percent to 38 percent of their G.D.P. to the combination. We came in 10th.
Bradley and Taylor put forth the argument that the things that make people healthy go beyond what we typically think of as health care. That is, access to employment, good housing, food security, and educational institutions all contribute to population health. I don't think this is a revolutionary thought.
But what is revolutionary is that they authors imply that the answer to our central question for US health care - "Do we get what we pay for?" - might not be the "no" we've always assumed, but a "yes." We just aren't spending enough, at least not on the proximal things that really matter. I don't think that it is that simple - it's hard to know what portion of social service spending actually improves health. But the discourse does need to move in this direction.
Furthermore, another neat aspect of this piece is that Bradley and Taylor's contention doesn't just apply to the macro-level health policy sphere. Imagine a primary care system that takes into account the socioeconomic realities of patients and creates interventions that use these insights to better provide care. A developing country example: subsidizing the transportation fees for HIV/AIDS patients who would otherwise find this to be a barrier and be unable to seek much needed health care. This sort of intervention may be equally important to any medications or lab tests in advancing the health of these patients. I'll talk more about this sort of "economic hotspotting" in a later post.
We studied 10 years’ worth of data and found that if you counted the combined investment in health care and social services, the United States no longer spent the most money — far from it. In 2005, for example, the United States devoted only 29 percent of gross domestic product to health and social services combined, while countries like Sweden, France, the Netherlands, Belgium and Denmark dedicated 33 percent to 38 percent of their G.D.P. to the combination. We came in 10th.
Bradley and Taylor put forth the argument that the things that make people healthy go beyond what we typically think of as health care. That is, access to employment, good housing, food security, and educational institutions all contribute to population health. I don't think this is a revolutionary thought.
But what is revolutionary is that they authors imply that the answer to our central question for US health care - "Do we get what we pay for?" - might not be the "no" we've always assumed, but a "yes." We just aren't spending enough, at least not on the proximal things that really matter. I don't think that it is that simple - it's hard to know what portion of social service spending actually improves health. But the discourse does need to move in this direction.
Furthermore, another neat aspect of this piece is that Bradley and Taylor's contention doesn't just apply to the macro-level health policy sphere. Imagine a primary care system that takes into account the socioeconomic realities of patients and creates interventions that use these insights to better provide care. A developing country example: subsidizing the transportation fees for HIV/AIDS patients who would otherwise find this to be a barrier and be unable to seek much needed health care. This sort of intervention may be equally important to any medications or lab tests in advancing the health of these patients. I'll talk more about this sort of "economic hotspotting" in a later post.
Sunday, December 4, 2011
Male Circumcision, HIV/AIDS and the "Real World"
This past week, PLoS Medicine put forth multi-piece expose (start with this lead/summary article) on medical male circumcision, its cost-effectiveness in combating HIV/AIDS and methods and challenges to scaling up this practice in Sub-Saharan Africa, where the epidemic is at its worst. The upshot of this series of papers was covered in a recent Scientific American piece (which quotes yours truly). To summarize, the argument is that medical male circumcision works (as demonstrated in three large randomized clinical trials, all conducted in Africa) and is cost-effective. Indeed, it may even be cost-saving, with high upfront costs that are easily recovered over a 10 year period. Challenges to scale-up include finding health care workers to carry out circumcisions (in a way that doesn't crowd-out provision of other important health care services), getting people to adopt the practice in a respectful, non-coercive yet effective way, especially in areas where there are strong traditional norms over circumcision, and dealing with any risk compensating behavior (if circumcised individuals think circumcision is protective, they may be more likely to engage in riskier sexual behaviors than they otherwise would - more on this in a later post).
Circumcision is one of those topics that seems to always bring with it a vociferous debate. Those opposed to the practice make their stance known quite vehemently. In my opinion, much of what is being spouted against medical male circumcision as a tool for HIV prevention is based on an incomplete understanding of the available evidence and already strong negative priors against the practice that are almost impossible to shift (for example, see this clip or refer to any of the comments to the aforementioned Scientific American article).
However, I think there is one oft-cited argument against medical male circumcision that is worth discussing further. In particular, opponents point to evidence from a 2009 UNAIDS study that uses recent survey data from 18 African countries and concludes that "there appears no clear pattern of association between male circumcision and HIV prevalence—in 8 of 18 countries with data, HIV prevalence is lower among circumcised men, while in the remaining 10 countries it is higher." This is contrast to the large randomized clinical trials mentioned above which show that circumcision reduces HIV rates by greater than 50%. The fact that the clinical trial results are not borne out in the sample survey data, opponents argue, means that circumcision does not work in "real world settings."
In a recent study, Brendan Maughan-Brown, Nicoli Nattrass, Jeremy Seekings, Alan Whiteside and I offer a different explanation for this differential set of findings. It has to do with the fact that the UNAIDS study looks at population that were circumcised in a multitude of settings (clinics, traditional healers) whereas the clinical trials focus on medical circumcision only. In practice, there great deal of heterogeneity in traditionally circumcising populations: some people do not have all of their foreskin removed, and others are circumcised several years after their peers. In our study population of blacks living in the Cape Town metro area, when we don't account for this heterogeneity, we find only a weak negative effect of circumcision on HIV positivity. However, once we "unpack" circumcision, we find that the practice actually has a strong negative association with the probability of testing HIV positive, provided it is done earlier and that there is complete removal of the foreskin.
These results suggest that the UNAIDS results may simply be due to measurement error. In a traditional setting, a circumcision is not a circumcision is not a circumcision. Treating every circumcised person the same introduces measurement error, and statistically it is well known that this would deflate the estimates of the impacts of the practice towards zero. So, the differential results between the UNAIDS findings and the randomized clinical trial findings is not that circumcision doesn't work in the real world. Rather, it is that we really need to understand better the heterogeneity in male circumcision and what can be done to ensure better outcomes for everyone involved.
Circumcision is one of those topics that seems to always bring with it a vociferous debate. Those opposed to the practice make their stance known quite vehemently. In my opinion, much of what is being spouted against medical male circumcision as a tool for HIV prevention is based on an incomplete understanding of the available evidence and already strong negative priors against the practice that are almost impossible to shift (for example, see this clip or refer to any of the comments to the aforementioned Scientific American article).
However, I think there is one oft-cited argument against medical male circumcision that is worth discussing further. In particular, opponents point to evidence from a 2009 UNAIDS study that uses recent survey data from 18 African countries and concludes that "there appears no clear pattern of association between male circumcision and HIV prevalence—in 8 of 18 countries with data, HIV prevalence is lower among circumcised men, while in the remaining 10 countries it is higher." This is contrast to the large randomized clinical trials mentioned above which show that circumcision reduces HIV rates by greater than 50%. The fact that the clinical trial results are not borne out in the sample survey data, opponents argue, means that circumcision does not work in "real world settings."
In a recent study, Brendan Maughan-Brown, Nicoli Nattrass, Jeremy Seekings, Alan Whiteside and I offer a different explanation for this differential set of findings. It has to do with the fact that the UNAIDS study looks at population that were circumcised in a multitude of settings (clinics, traditional healers) whereas the clinical trials focus on medical circumcision only. In practice, there great deal of heterogeneity in traditionally circumcising populations: some people do not have all of their foreskin removed, and others are circumcised several years after their peers. In our study population of blacks living in the Cape Town metro area, when we don't account for this heterogeneity, we find only a weak negative effect of circumcision on HIV positivity. However, once we "unpack" circumcision, we find that the practice actually has a strong negative association with the probability of testing HIV positive, provided it is done earlier and that there is complete removal of the foreskin.
These results suggest that the UNAIDS results may simply be due to measurement error. In a traditional setting, a circumcision is not a circumcision is not a circumcision. Treating every circumcised person the same introduces measurement error, and statistically it is well known that this would deflate the estimates of the impacts of the practice towards zero. So, the differential results between the UNAIDS findings and the randomized clinical trial findings is not that circumcision doesn't work in the real world. Rather, it is that we really need to understand better the heterogeneity in male circumcision and what can be done to ensure better outcomes for everyone involved.
Saturday, November 5, 2011
Infections and IQ
A well known fact about our world is that there are great disparities in average IQ scores across countries. In the past, some have tried to argue that this pattern be explained by innate differences in cognition across populations - some people are just innately smarter than others. Others have tried to attribute these to cultural factors. However, genetics and culture are likely not driving these differences in any meaningful sense. After all, another stylized fact is that average IQ scores have been going up markedly, within one or two generations, within any given country. These changes, also known as the Flynn Effect after the researcher who painstakingly documented them, speak against the genes story because they occurred far more quickly than one would expect from population-wide changes in the distribution of cognition-determining genes. The have occured too quickly to be explained by paradigm shifting social changes, as well.
So what gives? Enter Chris Eppig, a researcher at the University of New Mexico. In a recent piece in The Scientific American , he proposes that cross-country differences in IQ, as well as changes in IQ rates within a country over time, can be explained by exposure to infectious diseases early in life. The story goes something like this: infections early in life require energy to fight off. Energy during this age is primarily used for brain development (in infancy, it is thought that over 80% of calories are allocated to neurologic development). So if energy is diverted to fend off infections, it can't be used to develop cognitive endowments, and afflicted infants and children end up becoming adults that do poorly on IQ tests.
In the piece, Eppig cites some of his work linking infectious disease death rates in countries to average IQ scores. His models control for country income and a few other important macroeconomic variables. His evidence, while not proof of a causal relationship, is certainly provocative. So provocative in fact that I ended up trying to build a stronger causal story between early childhood infections and later life cognitive outcomes. In a recent paper (cited in the above Scientific American article), I examine the impact of early life exposure to malaria on later life performance on a visual IQ test. I use a large-scale malaria eradication program in Mexico (1957) as a quasi-experiment to prove causality. Basically, I find that individuals born in states with high rates of malaria prior to eradication - the area that gained most from eradication - experienced large gains in IQ test scores after eradication relative those born in states with low pre-intervention malaria rates, areas that did not benefit as much from eradication (see this Marginal Revolution piece for a slightly differently worded explanation).
My paper also looks at the mechanisms linking infections and cognition. One possibility is the biological model described above - infections divert nutritional energy away from brain development. However, I also find evidence of a second possibility: parents respond to initial differences in cognition or health due to early life infections and invest in their children accordingly. In the Mexican data, children who were less afflicted by malaria thanks to the eradication program started school earlier than those who were more afflicted. Because a child's time is the domain of parental choice, this suggests that parents reinforce differences in the way their children are (- erhaps they feel that smarter children will be smarter adults, and so investments in their schooling will yield a higher rate of return - and that this can modulate the relationship between early life experiences and adulthood outcomes.
So what gives? Enter Chris Eppig, a researcher at the University of New Mexico. In a recent piece in The Scientific American , he proposes that cross-country differences in IQ, as well as changes in IQ rates within a country over time, can be explained by exposure to infectious diseases early in life. The story goes something like this: infections early in life require energy to fight off. Energy during this age is primarily used for brain development (in infancy, it is thought that over 80% of calories are allocated to neurologic development). So if energy is diverted to fend off infections, it can't be used to develop cognitive endowments, and afflicted infants and children end up becoming adults that do poorly on IQ tests.
In the piece, Eppig cites some of his work linking infectious disease death rates in countries to average IQ scores. His models control for country income and a few other important macroeconomic variables. His evidence, while not proof of a causal relationship, is certainly provocative. So provocative in fact that I ended up trying to build a stronger causal story between early childhood infections and later life cognitive outcomes. In a recent paper (cited in the above Scientific American article), I examine the impact of early life exposure to malaria on later life performance on a visual IQ test. I use a large-scale malaria eradication program in Mexico (1957) as a quasi-experiment to prove causality. Basically, I find that individuals born in states with high rates of malaria prior to eradication - the area that gained most from eradication - experienced large gains in IQ test scores after eradication relative those born in states with low pre-intervention malaria rates, areas that did not benefit as much from eradication (see this Marginal Revolution piece for a slightly differently worded explanation).
My paper also looks at the mechanisms linking infections and cognition. One possibility is the biological model described above - infections divert nutritional energy away from brain development. However, I also find evidence of a second possibility: parents respond to initial differences in cognition or health due to early life infections and invest in their children accordingly. In the Mexican data, children who were less afflicted by malaria thanks to the eradication program started school earlier than those who were more afflicted. Because a child's time is the domain of parental choice, this suggests that parents reinforce differences in the way their children are (- erhaps they feel that smarter children will be smarter adults, and so investments in their schooling will yield a higher rate of return - and that this can modulate the relationship between early life experiences and adulthood outcomes.
Saturday, October 29, 2011
Good and Bad Epidemiology and Other Interesting Links
1. The incomparably intelligent and eloquent Sanjay Basu on how doctor house calls of the olden days could return - in the form of targeted efforts to reduce preventative disease and hospitalizations on the basis of cutting edge epidemiology.
2. A man after my own heart, Dr. Ben Goldacare, an evidence based medicine expert, rails against bad epidemiology studies (you know, the kind in the news that like say coffee is protective against cancer or something like this, only to be overturned 180 degrees two months later) in this entertaining TED talk. Some useful pointers about how to differentiate between junk and good research as well as a good summary of causal inference. (HT: Jeremy Green)
3. Apparently there is enough sense to go around for all of us.
4. Asif Mandvi of The Daily Show lampoons the Republican candidates position on science and scientific knowledge in this great clip. Its pretty funny, until you realize that the candidates are actually serious. Then its a little scary. (HT: Kim Kopecky)
5. How does the recession and being out of work influence our physical activity? And what are its implications for health? Gregory Colman and Dhaval Dave explore these issues in an interesting recent NBER working paper.
2. A man after my own heart, Dr. Ben Goldacare, an evidence based medicine expert, rails against bad epidemiology studies (you know, the kind in the news that like say coffee is protective against cancer or something like this, only to be overturned 180 degrees two months later) in this entertaining TED talk. Some useful pointers about how to differentiate between junk and good research as well as a good summary of causal inference. (HT: Jeremy Green)
3. Apparently there is enough sense to go around for all of us.
4. Asif Mandvi of The Daily Show lampoons the Republican candidates position on science and scientific knowledge in this great clip. Its pretty funny, until you realize that the candidates are actually serious. Then its a little scary. (HT: Kim Kopecky)
5. How does the recession and being out of work influence our physical activity? And what are its implications for health? Gregory Colman and Dhaval Dave explore these issues in an interesting recent NBER working paper.
Thursday, October 27, 2011
Discrimination in the Shadows
Two new papers looking at various aspects of discrimination in product and labor markets. The first, by Ian Ayres and coauthors, examines baseball card sales:
We investigate the impact of seller race in a field experiment involving baseball card auctions on eBay. Photographs showed the cards held by either a dark-skinned/African-American hand or a light-skinned/Caucasian hand. Cards held by African-American sellers sold for approximately 20% ($0.90) less than cards held by Caucasian sellers, and the race effect was more pronounced in sales of minority player cards. Our evidence of race differentials is important because the on-line environment is well controlled (with the absence of confounding tester effects) and because the results show that race effects can persist in a thick real-world market such as eBay.
The second looks at skilled immigrant labor in Canada. Canada, like many other first world countries, has made it a policy to strongly select for skilled immigrants to augment their workforce. Unfortunately, these immigrants do not do as well as one would hope in the labor market. Philip Oreopoulos explores this issue in greater depth:
Thousands of randomly manipulated resumes were sent in response to online job postings in Toronto to investigate why immigrants, allowed in based on skill, struggle in the labor market. The study finds substantial discrimination across a variety of occupations towards applicants with foreign experience or those with Indian, Pakistani, Chinese, and Greek names compared with English names. Listing language fluency, multinational firm experience, education from highly selective schools, or active extracurricular activities had no diminishing effect. Recruiters justify this behavior based on language skill concerns but fail to fully account for offsetting features when listed.
While they speak for themselves, here are a few collective comments on these papers:
1. Both illustrate the power of audit studies, where researchers elicit real-time behavioral responses in the field to some often innocuous stimuli. Resume experiments have a long history in economics and sociology. The EBay thing is new, and quite innovative.
2. Audit studies give us an example of behavior, but can further be extended to think about mechanisms and policy. One reason I like the Oreopoulos paper is that his randomization involved an explicit countersignal to having an immigrant last name. Unfortuntately, it didn't work to reverse the discriminatory effect, but it is informative that signaling language skills failed. What would be nice is to further extend this, both to other policies, but also to a further elucidation of mechanisms. I think qualitative work could be very useful in this regard. (My colleagues and I did this in a paper about corruption).
3. Both of these studies reveal that taste-based or statistical discrimination is pretty deep seated, though it may lurk in the shadows. So what to do about this? Jumping from (2), I hope the next wave of experiments look at different sorts of policies. Are there other nudges that can be used to counteract these forces? Or will immigrants have their change from Shankaranarayan to Steve in order to get jobs?
We investigate the impact of seller race in a field experiment involving baseball card auctions on eBay. Photographs showed the cards held by either a dark-skinned/African-American hand or a light-skinned/Caucasian hand. Cards held by African-American sellers sold for approximately 20% ($0.90) less than cards held by Caucasian sellers, and the race effect was more pronounced in sales of minority player cards. Our evidence of race differentials is important because the on-line environment is well controlled (with the absence of confounding tester effects) and because the results show that race effects can persist in a thick real-world market such as eBay.
The second looks at skilled immigrant labor in Canada. Canada, like many other first world countries, has made it a policy to strongly select for skilled immigrants to augment their workforce. Unfortunately, these immigrants do not do as well as one would hope in the labor market. Philip Oreopoulos explores this issue in greater depth:
Thousands of randomly manipulated resumes were sent in response to online job postings in Toronto to investigate why immigrants, allowed in based on skill, struggle in the labor market. The study finds substantial discrimination across a variety of occupations towards applicants with foreign experience or those with Indian, Pakistani, Chinese, and Greek names compared with English names. Listing language fluency, multinational firm experience, education from highly selective schools, or active extracurricular activities had no diminishing effect. Recruiters justify this behavior based on language skill concerns but fail to fully account for offsetting features when listed.
While they speak for themselves, here are a few collective comments on these papers:
1. Both illustrate the power of audit studies, where researchers elicit real-time behavioral responses in the field to some often innocuous stimuli. Resume experiments have a long history in economics and sociology. The EBay thing is new, and quite innovative.
2. Audit studies give us an example of behavior, but can further be extended to think about mechanisms and policy. One reason I like the Oreopoulos paper is that his randomization involved an explicit countersignal to having an immigrant last name. Unfortuntately, it didn't work to reverse the discriminatory effect, but it is informative that signaling language skills failed. What would be nice is to further extend this, both to other policies, but also to a further elucidation of mechanisms. I think qualitative work could be very useful in this regard. (My colleagues and I did this in a paper about corruption).
3. Both of these studies reveal that taste-based or statistical discrimination is pretty deep seated, though it may lurk in the shadows. So what to do about this? Jumping from (2), I hope the next wave of experiments look at different sorts of policies. Are there other nudges that can be used to counteract these forces? Or will immigrants have their change from Shankaranarayan to Steve in order to get jobs?
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