Results for “cohort” 290 found
Accurate genomic prediction of human height
They used to say this couldn’t be done:
We construct genomic predictors for heritable and extremely complex human quantitative traits (height, heel bone density, and educational attainment) using modern methods in high dimensional statistics (i.e., machine learning). Replication tests show that these predictors capture, respectively, ~40, 20, and 9 percent of total variance for the three traits. For example, predicted heights correlate ~0.65 with actual height; actual heights of most individuals in validation samples are within a few cm of the prediction. The variance captured for height is comparable to the estimated SNP heritability from GCTA (GREML) analysis, and seems to be close to its asymptotic value (i.e., as sample size goes to infinity), suggesting that we have captured most of the heritability for the SNPs used. Thus, our results resolve the common SNP portion of the “missing heritability” problem – i.e., the gap between prediction R-squared and SNP heritability. The ~20k activated SNPs in our height predictor reveal the genetic architecture of human height, at least for common SNPs. Our primary dataset is the UK Biobank cohort, comprised of almost 500k individual genotypes with multiple phenotypes. We also use other datasets and SNPs found in earlier GWAS for out-of-sample validation of our results.
While I don’t find “within a few centimeters” to be especially impressive, the question is still “what’s next?”
The authors on the paper are
Tuesday assorted links
1. “We find that relative to males in the same cohort, female economists are less likely (by about 14%) to have received tenure and promotion eight years post-graduation.” And Kevin says reforming tenure is not nearly enough.
2. Most legacy applicants fits the academic profile of the colleges to which they are admitted. I would stress this is a) revenue-maximizing, b) still deeply unfair, c) still pragmatically a good thing, and d) an indictment of how institutions currently think about “academic profile.”
3. On the origin of municipal segregation ordinances.
4. The new Shanghai rankings for economics departments. GMU Law also in the top 30. And Lynne Kiesling moves to Purdue, congratulations!
5. How will Lagos cope with its population?
6. David Brooks on moderates (NYT).
Hospital patients treated by older physicians are more likely to die
BMJ: In a national sample of elderly Medicare beneficiaries admitted to hospital with medical conditions, we found that patients treated by older physicians had higher 30 day mortality than those cared for by younger physicians, despite similar patient characteristics. These associations were found among physicians with low and medium volumes of patients but not among those with high volumes.
…Our findings suggest that within the same hospital, patients treated by physicians aged <40 have 0.85 times the odds of dying (1.00/1.17) or an 11% lower probability of dying (10.8/12.1), compared with patients cared for by physicians aged ≥60 (table 2⇑). This difference in mortality is comparable with the impact of statins for the primary prevention of cardiovascular mortality on all cause mortality (odds ratio of 0.86)39 or the impact of β blockers on mortality among patients with myocardial infarction (incidence rate ratio of 0.86),40 indicating that our observed difference in mortality is not only statistically significant but arguably clinically significant. In addition, if our results are causal, an adjusted risk difference of 1.3 percentage points suggests that for every 77 patients treated by doctors aged ≥60, one fewer patient would die within 30 days of admission if those patients were cared for by physicians aged <40.
The paper has data on over 700,000 Medicare admissions and over 18 thousand hospitalist physicians. Physicians are assigned to patients more or less randomly depending on admission time so there are no significant differences between patients assigned to younger and older physicians. Older physicians are more likely to be male and, of course, to be trained during a different time period so the paper can’t fully distinguish age effects from cohort effects. The authors do find that older physicians who work a lot perform well–perhaps these physicians update their training or perhaps they are a self-selected vigorous sample. Continuing medical education and assessment requirements are probably very valuable.
Hat tip: Eric Topol.
Has intergenerational mobility finally been shown to have declined?
If you recall, Robert D. Putnam, in his last book, expressed surprise that Chetty and Hendren, et.al. (2014) did not find evidence of a decline in intergenerational mobility. Putnam predicted that researchers would find such evidence soon enough. After all, it seems the returns to education have been rising, geographic mobility has been falling, market concentration is up slightly, life expectancy is behaving in funny ways, and regional disparities seem to have grown. Chetty and Grusky, et.al. (2016) seemed to paint a more pessimistic picture than did his work from a few years ago, and now we have a new paper by Jonathan Davis and Bhashkar Mazumder:
We demonstrate that intergenerational mobility declined sharply for cohorts born between 1942 and 1953 compared to those born between 1957 and 1964. The former entered the labor market prior to the large rise in inequality that occurred around 1980 while the latter cohorts entered the labor market largely afterwards. We show that the rank-rank slope rose from 0.27 to 0.4 and the IGE rose from 0.35 to 0.51. The share of children whose income exceeds that of their parents fell by about 3 percentage points. These findings suggest that relative mobility fell by substantially more than absolute mobility.
So far this seems to be the current version of the final word. The authors also argue, by the way, that Chetty (2016) is somewhat too pessimistic, though correct in suggesting mobility has indeed fallen.
By the way, this seems to be the best link for a download.
American sexual frequency estimates of the day
American adults had sex about nine fewer times per year in the early 2010s compared to the late 1990s in data from the nationally representative General Social Survey, N = 26,620, 1989–2014. This was partially due to the higher percentage of unpartnered individuals, who have sex less frequently on average. Sexual frequency declined among the partnered (married or living together) but stayed steady among the unpartnered, reducing the marital/partnered advantage for sexual frequency. Declines in sexual frequency were similar across gender, race, region, educational level, and work status and were largest among those in their 50s, those with school-age children, and those who did not watch pornography. In analyses separating the effects of age, time period, and cohort, the decline was primarily due to birth cohort (year of birth, also known as generation). With age and time period controlled, those born in the 1930s (Silent generation) had sex the most often, whereas those born in the 1990s (Millennials and iGen) had sex the least often. The decline was not linked to longer working hours or increased pornography use. Age had a strong effect on sexual frequency: Americans in their 20s had sex an average of about 80 times per year, compared to about 20 times per year for those in their 60s. The results suggest that Americans are having sex less frequently due to two primary factors: An increasing number of individuals without a steady or marital partner and a decline in sexual frequency among those with partners.
Here is the article, by Twenge, Sherman, and Wells, via the excellent Kevin Lewis.
The Long-Term Impact of Price Controls in Medicare Part D
There is a new paper on this topic, by Gigi Moreno, Emma van Eijndhoven, Jennifer Benner, and Jeffrey Sullivan. The upshot is to beware price controls:
Price controls for prescription drugs are once again at the forefront of policy discussions in the United States. Much of the focus has been on the potential short-term savings – in terms of lower spending – although evidence suggests price controls can dampen innovation and adversely affect long-term population health. This paper applies the Health Economics Medical Innovation Simulation, a microsimulation of older Americans, to estimate the long-term impacts of government price setting in Medicare Part D, using pricing in the Federal Veterans Health Administration program as a proxy. We find that VA-style pricing policies would save between $0.1 trillion and $0.3 trillion (US$2015) in lifetime drug spending for people born in 1949–2005. However, such savings come with social costs. After accounting for innovation spillovers, we find that price setting in Part D reduces the number of new drug introductions by as much as 25% relative to the status quo. As a result, life expectancy for the cohort born in 1991–1995 is reduced by almost 2 years relative to the status quo. Overall, we find that price controls would reduce lifetime welfare by $5.7 to $13.3 trillion (US$2015) for the US population born in 1949–2005.
I would insist that we do not have good enough models of the innovation process to really understand the price elasticity of supply. Nonetheless it is surely not zero, and under plausible assumptions the price controls are a bad idea.
We need a new rooftop chant: “Beware analyses that neglect supply elasticities,” to sweet cadences of course. They should play that on AM radio as well.
For the pointer I thank the still excellent Kevin Lewis.
Sunday assorted links
1. Good thread on Tillerson. Steve Coll tries to make Tillerson sound bad, I am not sure he succeeds. Here is Rob Stavins on Tillerson. I disagree with what seems to be Trump’s intended Russia policy, but I’ve known plenty of businessmen who have done deals with unpleasant foreign powers and I have never doubted their loyalties to the United States. I see those issues being blurred and smushed together in a new kind of odd reverse McCarthyism.
2. Redux of my earlier post “Modeling Vladimir Putin.”
3. Westworld and the American Civil War.
4. “A person born in 1940 was, by the time he was 30, close to his peak earning point. A person born in 1980, by the time he is 30, is further away from a higher peak earning point. Thus, you are not comparing the same type of birth cohorts.” Link here, and a bit more here.
5. “”I put out early,” she says.” (NYT)
Upward Mobility and Discrimination: Asians and African Americans
Asians in America faced heavy discrimination and animus in the early twentieth century. Yet, after institutional restrictions were lifted in the late 1940s, Asian incomes quickly converged to white incomes. Why? In the politically incorrect paper of the year (ungated) Nathaniel Hilger argues that convergence was due to market forces subverting discrimination. First, a reminder about the history and strength of discrimination against Asians:
Foreign-born Asians were barred from naturalization by the Naturalization Act of 1790. This Act excluded Asians from citizenship and voting except by birth, and created the important new legal category of “aliens ineligible for citizenship”…Asians experienced mob violence including lynchings and over 200 “roundups” from 1849-1906 (Pfaelzer, 2008), and hostility from anti-Asian clubs much like the Ku Klux Klan (e.g., the Asiatic Exclusion League, Chinese Exclusion League, Workingmen’s Party of CA), to an extent that does not appear to have any counterpart for blacks in CA history. Both Asians and blacks in CA could not testify against a white witness in court from 1853-73 (People v. Hall, 1853, see McClain, 1984), limiting Asians’ legal defense against white aggression. The Chinese Exclusion Act of 1882 and the “Gentlemen’s Agreement” in 1907 barred further immigration of all “laborers” from China and Japan.
…Asians have also faced intense economic discrimination. Many cities and states levied discriminatory taxes and fees on Asians (1852 Foreign Miner’s Tax, 1852 Commutation Tax, 1860 Fishing License, 1862 Police Tax, 1870 “queue” ordinance, 1870 sidewalk ordinance, and many others). Many professional schools and associations in CA excluded Asians (e.g., State Bar of CA), as did most labor unions (e.g., Knights of Labor, American Federation of Labor), and many employers declined to hire Asians well into the 20th century (e.g., Mears, 1928, p. 194-204). From 1913-23, virtually all western states passed increasingly strict Alien Land Acts that prohibited foreign-born Asians from owning land or leasing land for extended periods. Asians also faced laws against marriage to whites (1905 amendment to Section 60 of the CA Civil Code) and U.S. citizens (Expatriation Act 1907, Cable Act 1922). From 1942-46, the US forcibly relocated over 100,000 mainland Japanese Americans (unlike other Axis nationalities, e.g. German or Italian Americans) to military detention camps, in practice destroying a large share of Japanese American wealth. In contrast, blacks in CA were eligible for citizenship and suffrage, were officially (though often not de facto) included in CA professional associations and labor unions that excluded Asians, were not covered by the Alien Land Acts, and were not confined or expropriated during WWII.
Despite this intense discrimination, Asian (primarily Japanese and Chinese) incomes converged to white incomes as early as 1960 and certainly by 1980. One argument is that Asians invested so heavily in education that convergence has been overstated but Hilger shows that convergence occurred conditional on education. Similarly, convergence was not a matter of immigration or changing demographics. Instead, Hilger argues that once institutional discrimination was eased in the 1940s, market forces enforced convergence. As I wrote earlier, profit maximization subverts discrimination by employers:
If the wages of X-type workers are 25% lower than those of Y-type workers, for example, then a greedy capitalist can increase profits by hiring more X workers. If Y workers cost $15 per hour and X workers cost $11.25 per hour then a firm with 100 workers could make an extra $750,000 a year. In fact, a greedy capitalist could earn more than this by pricing just below the discriminating firms, taking over the market, and driving the discriminating firms under.
If that theory is true, however, then why haven’t black incomes converged? And here is where the paper gets into the politically incorrect:
Modern empirical work has indicated that cognitive test scores—interpreted as measures of productivity not captured by educational attainment—can account for a large share of black-white wage and earnings gaps (Neal and Johnson, 1996; Johnson and Neal, 1998; Fryer, 2010; Carruthers and Wanamaker, 2016). This literature documents large black-white test score gaps that emerge early in childhood (Fryer and Levitt, 2013), persist into adulthood, and appear to reflect genuine skills related to labor market productivity rather than racial bias in the testing instrument (Neal and Johnson, 1996). While these modern score gaps
have not been fully accounted for by measured background characteristics (Neal, 2006; Fryer and Levitt, 2006; Fryer, 2010), they likely relate to suppressed black skill acquisition during slavery and subsequent educational discrimination against blacks spanning multiple generations (Margo, 2016).
…A basic requirement of this hypothesis is that Asians in 1940 possessed greater skills than blacks, conditional on education. In fact, previous research on Japanese Americans in CA support this theory. Evidence from a variety of cognitive tests given to students in CA in the early 20th century suggest test score parity of Japanese Americans with local whites after accounting for linguistic and cultural discrepancies, and superiority of Japanese Americans in academic performance in grades 7-12 (Ichihashi, 1932; Bell, 1935).
Hilger supplements these earlier findings with a small dataset from the Army General Classification Test:
…these groups’ cognitive test performance can be studied using AGCT scores in WWII enlistment records from 1943. Remarkably, these data are large enough to compare Chinese, blacks and whites living in CA for these earlier cohorts. In addition, this sample contains enough young men past their early 20s to compare test scores conditional on final educational attainment, which can help to shed light on mechanisms underlying the conditional earnings gap documented above.
Figure XII plots the distribution of normalized test score residuals by race from an OLS regression of test z-scores on dummies for education and age. Chinese Americans and whites have strikingly similar conditional skill distributions, while the black skill distribution lags behind by nearly a full standard deviation. Table VIII shows that this pattern holds separately within broad educational categories. These high test scores of Chinese Americans provide strong evidence that the AGCT was not hopelessly biased against non-whites, as Neal and Johnson (1996) also find for the AFQT (the successor to the AGCT) in more recent cohorts.
From Hilger’s conclusion:
Using a large and broadly representative sample of WWII enlistee test scores from 1943 both on their own and matched to the 1940 census, I document the striking fact that these test scores can account for a large share of the black, but not Asian, conditional earnings gap in 1940. This result suggests that Asians earnings gaps in 1940 stemmed primarily from taste-based or some other non-statistical discrimination, in sharp contrast with the black earnings gap which largely reflected statistical discrimination based on skill gaps inherited from centuries of slavery and educational exclusion. The rapid divergence of conditional earnings between CA-born Asians and blacks after 1940—once CA abandoned its most severe discriminatory laws and practices—provides the first direct empirical evidence in support of the hypothesis of Arrow (1972) and others that competitive labor markets tend to eliminate earnings gaps based purely on taste-based but not statistical discrimination.
Hilger’s other research is here.
Dominican Republic fact of the day
I find that a free trade zone in a province delays the age of first marriage by 1.6 years. Moreover, the probability of early marriage is reduced by 30 percentage points. The results are primarily driven by women that were in school at the time of the opening. The free trade zones increase women’s years of education, especially during secondary school.
That is from a paper by Maria Micaela Sviatschi (pdf), who is on the job market from Columbia University. Hers is one of the most interesting portfolios I have seen this year.
Another paper of hers shows that indoor prostitution lowers sex crime (pdf). Her job market paper (pdf) is on how childhood exposure to illegal activities can breed criminal behavior later in life, here is the abstract:
This paper shows that exposing children to illegal labor markets makes them more likely to be criminals as adults. I exploit the timing of a large anti-drug policy in Colombia that shifted cocaine production to locations in Peru that were well-suited to growing coca. In these areas, children harvest coca leaves and transport processed cocaine. Using variation across locations, years, and cohorts, combined with administrative data on the universe of individuals in prison in Peru, affected children are 30% more likely to be incarcerated for violent and drug-related crimes as adults. The biggest impacts on adult criminality are seen among children who experienced high coca prices in their early teens, the age when child labor responds the most. No effect is found for individuals that grow up working in places where the coca produced goes primarily to the legal sector, implying that it is the accumulation of human capital specific to the illegal industry that fosters criminal careers. As children involved in the illegal industry learn how to navigate outside the rule of law, they also lose trust in government institutions. However, consistent with a model of parental incentives for human capital investments in children, the rollout of a conditional cash transfer program that encourages schooling mitigates the effects of exposure to illegal industries. Finally, I show how the program can be targeted by taking into account the geographic distribution of coca suitability and spatial spillovers. This paper takes a first step towards understanding how criminals are formed by unpacking the way in which crime-specific human capital is developed at the expense of formal human capital in bad locations.
She has numerous papers and virtually all of them look quite interesting. Other topics include whether domestic violence lowers human capital investment and the economic effects of the (former) gang truce in El Salvador. Here is her basic research portfolio.
The panel data great stagnation and also student debt edition, courtesy Justin Weidner
Yes it supports what many of us have been saying for what is now quite a few years:
Using panel data on individual labor income from 1957 to 2013, we document two empirical facts about the distribution of lifetime income in the United States. First, we show that from the cohort that entered the labor market in 1968 to the one entered in 1983, three-quarters of U.S. workers did not experience any increase in lifetime income. Further, during the same period, median lifetime income actually declined by 10-20% for men but increased by 20-30% for women, yet the latter increase was not enough to offset the decline for males because of the very low lifetime income of the earlier cohorts of females. Accounting for rising employer provided health and retirement benefits partly mitigates these findings, but does not overturn them. Much of these changes across cohorts that we document come from the large changes in starting income levels (i.e., at age 25) across cohorts. Based on partial life-cycle income observed for cohorts that are currently in the labor market, the stagnation of lifetime incomes is unlikely to reverse. Second, turning to inequality in lifetime incomes, we find that it has increased significantly within each gender group, but the closing lifetime gender gap has kept overall lifetime inequality virtually flat.
That is from forthcoming work by Justin Weidner, Fatih Guvenen, Greg Kaplan, and Jae Song. Right now I am looking at Weidner’s site, his job market paper (pdf) is also quite interesting:
I demonstrate that rise in debt since 1990 has contributed to income stagnation, lowering affected graduates’ income by 1.9\% on average. Because it does not distort occupational choices, an income contingent repayment scheme would increase income for constrained graduates by 3.5% on average.
I look forward to following his work in years to come.
The new economics of cybercrime
“We’re living through an historic glut of stolen data,” explains Brian Krebs, who writes the blog Krebs on Security. “More supply drives the price way down, and there’s so much data for sale, we’re sort of having a shortage of buyers at this point.”
…But cybercriminals’ most crucial adaptation in recent years has little to do with their technical tools and everything to do with their business model: They have started selling stolen data back to its original owners. To keep cybercrime profitable, criminals needed to find a new cohort of potential buyers, and they did: all of us. At the heart of this new business model for cybercrime is the fact that individuals and businesses, not retailers and banks, are the ones footing the bill for data breaches.
Here is the full Josephine Wolff piece.
College socializes people into the mentality of the affluent
There is a paper on that theme (pdf) by Tali Mendelberg, Katherine T.McCabe, and Adam Thal, here is the abstract:
Affluent Americans support more conservative economic policies than the non-affluent, and government responds disproportionately to these views. Yet little is known about the emergence of these consequential views. We develop, test and find support for a theory of class cultural norms: these preferences are partly traceable to socialization that occurs on predominately affluent college campuses, especially those with norms of financial gain, and especially among socially embedded students. The economic views of the student’s cohort also matter, in part independently of affluence. We use a large panel dataset with a high response rate and more rigorous causal inference strategies than previous socialization studies. The affluent campus effect holds with matching, among students with limited school choice, and in a natural experiment, and passes placebo tests. College socialization partly explains why affluent Americans support economically conservative policies.
For the pointer I thank Nathaniel Bechhofer. One implication is that left-wing, politically correct top private universities don’t actually turn out such left-wing individuals, all things considered. You can think of their sillier college views as part of a broader life cycle, portfolio story. I also take this to be further evidence of just how much education is about socialization, rather than the explicit mastery of scholarly information.
What happens if you expand higher education?
This is based on Italian data from the 1960s:
However, I also find that those induced to enroll earned no more than students in earlier cohorts who were denied access to university. I reconcile these surprising results by showing that the education expansion reduced returns to skill and lowered university learning through congestion and peer effects. I also demonstrate that apparently inframarginal students were significantly affected: the most able of them abandoned STEM majors rather than accept lower returns and lower human capital.
Uh-oh. The good news, however, is that the children of these individuals seem to have ended up in higher-paying jobs.
That is from Nicola Bianchi (pdf), he is now at Northwestern. For the pointer I thank Robin Gaster.
From the comments, on Amish health and health care
I was just at two Amish weddings and would add a few observations:
– I wonder what they’d find for a later cohort. Amish folks born between 1890 and 1921 were almost all farmers. Today, fewer than 10% are. Most have far more sedentary jobs–though not as sedentary as mine. But they still eat as if they were out in the fields all day. Obesity is rampant and growing. Also, the diet has changed. The Amish eat a lot of processed, brand name food. They do have their own kitchen gardens, but salads are covered in dressing and cheese. In many homes, every meal (even breakfast!) comes with pie as desert.
– Nobody is left alone in old age. I had a long talk with an older Amish woman who couldn’t believe that, in NYC, some people live alone, interact with no close relatives or friends, have no one to watch over them. Her husband told a story of a very ornery old man with no children or wife who nobody likes but, still, people visit regularly to make sure he’s OK and to give him comfort.
– They absolutely use hospitals for urgent and emergent care. There are big fundraising auctions all the time to help those with big bills. And the church district will also help.
Yes, that is the Adam Davidson.
The Amish and the marginal value of health care
Or is that the infra-marginal value?:
…we have compared lifespan in the Old Order Amish (OOA), a population with historically low use of medical care, with that of Caucasian participants from the Framingham Heart Study (FHS), focusing on individuals who have reached at least age 30 years.
Analyses were based on 2,108 OOA individuals from the Lancaster County, PA community born between 1890 and 1921 and 5,079 FHS participants born approximately the same time. Vital status was ascertained on 96.9% of the OOA cohort through 2011 and through systematic follow-up of the FHS cohort. The lifespan part of the study included an enlargement of the Anabaptist Genealogy Database to 539,822 individuals, which will be of use in other studies of the Amish. Mortality comparisons revealed that OOA men experienced better longevity (p<0.001) and OOA women comparable longevity than their FHS counterparts.
That is from a 2012 PLOS paper, by Braxton D. Mitchell, et.al., via Ben Southwood.