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Archive for June 2008

Fast times in Jamaica

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Ever wonder how Jamaica, a country of 3 million people, can compete with the US and totally dominate all of Europe and Asia when it comes to the sprints? China has spent billions on a Soviet-style sports program that selects promising athletes at a young age and sends them to special sports schools. When Liu Xiang won the 110 hurdles at the last Olympics, Chinese officials referred to his gold as the “heaviest” of all medals won by Chinese in Athens. There is no lack of Chinese desire to win sprint gold — Liu Xiang is the biggest sports star in China after Yao Ming! Similarly, the US and Europe have far more money than Jamaica for training facilities, coaches, scholarships, stipends, etc. World class athletes in Jamaica train on a grass track and in weight rooms with rusty barbells. Most US high schools have superior facilities. (See video here.)

The times below are phenomenal — they rival the times put up this weekend in Eugene at the US Olympic trials, and totally surpass the performance of any European or Asian nation.

World record-holder Usain Bolt beat former record-holder Asafa Powell in the 100-meter final in Jamaica’s Olympic trials, finishing in 9.85 seconds in Kingston.

Powell was second in 9.97. Last month in New York, Bolt ran a 9.72 to break Powell’s world record of 9.74.

Kerron Stewart won the women’s 100 in 10.80, the second-fastest time by a Jamaican woman ever. Shelly-Ann Fraster was second in 10.85, Sherone Simpson followed in 10.87 and world champion Veronica Campbell-Brown was fourth in 10.87.

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June 30, 2008 at 5:26 pm

Higher education and human capital II

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I thought I’d also link to some interesting data from a paper by UT Austin economist Daniel Hamermesh, discussed here on the NYTimes Freakonomics blog.

Their survey covered UT Austin alumni between the ages of 23 and 43, revealing enormous variations in average earnings between different majors. Not surprisingly, the business majors and engineers tend to be high earners. However, the highest earners of all are the Plan II (honors college) alumni, who have by far the highest average SAT scores (1364). Note the huge variance within each major (SD = number in parentheses below the mean value), in particular for business, natural sciences and Plan II. For these majors the standard deviation is larger than the mean, suggesting, perhaps, that a few millionaires (startup founders, entrepreneurs?) are skewing the results.

The effect of college curriculum on earnings: …Clearly, there are large differences across major in average earnings, with the highest-earning majors (Honors Plan II, and “Hard” Business) having averages almost three times that of the lowest (Education). Much of the differences across majors must be due to differences in what the students bring to and do at the University. Students in the higher-earning majors generally have higher SAT totals upon entry, and the fractions of students taking upper-division math and science courses and doing well in them are greater too. The differences are also consistent with the results of differential effort in the labor market and male-female differences in earnings. Thus respondents in the higher-earning majors tend to state that they work longer hours than those in lower-earning majors; and except for the Honors Plan II major, the fraction of women in the higher-earning majors is lower. On the other hand, advanced degrees are more prevalent among those graduates who have majored in subjects that eventually generate lower earnings. Family incomes in the areas where the students attended high school do not differ across majors …

…Even within major, taking more upper-division science or math courses and doing better in them raise eventual earnings. While the effects are not highly significant statistically, the t-statistics generally exceed 1.28. A student who takes 15 credits of upper-division science and math courses and obtains a B average in them will earn about 10 percent more than an otherwise identical student in the same major … who takes no upper-division classes in these areas. There is clearly a return to taking these difficult courses. This holds true even after we have adjusted for differences in mathematical ability by using the total SAT score … . The importance of access to this information should not be underestimated. Estimated earnings differences across majors are substantially higher (e.g., the premium for “hard” business rises to 64 log points, that for engineering to 50 log points) when the information on science and math courses is excluded from the equation in Column (1).

Click on the figure below for a larger, more readable version.


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June 29, 2008 at 8:15 pm

Higher education and human capital

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What good is higher education? The conventional view is that, in addition to producing a well-informed citizenry, it builds important human capital and raises national productivity. But what is the evidence for these assertions? In policy debates we are typically presented with faulty logic: workers in desirable, high value-added jobs (e.g., at Google or Biogen) tend to have lots of education. Therefore, if we want Americans to have such jobs we had better expand access to higher education. The counter argument, that returns to society as a whole from education diminish as access increases beyond the cognitive elite, is given below by a well-known curmudgeon and psychometric realist:

Brutal, just brutal: …There is no magic point at which a genuine college-level education becomes an option, but anything below an IQ of 110 is problematic. If you want to do well, you should have an IQ of 115 or higher. Put another way, it makes sense for only about 15% of the population, 25% if one stretches it, to get a college education. And yet more than 45% of recent high school graduates enroll in four-year colleges. Adjust that percentage to account for high-school dropouts, and more than 40% of all persons in their late teens are trying to go to a four-year college–enough people to absorb everyone down through an IQ of 104.

Note the claim is not that benefits from higher education are zero for the average student, but merely that they diminish significantly as we expand access. At some point we need to consider whether the marginal cost exceeds the marginal benefit. No amount of schooling will turn an average student into a materials engineer, tax lawyer or derivatives trader.

I’m afraid these kinds of thoughts lurk in the minds of most professors these days — I’ve heard them discussed many times. Why can’t my students write? Why can’t my students do simple math? Does the bottom half of the class really absorb anything from my lectures? Is science just too difficult for some people? If I showed you some of the emails I receive from students in my physics 101 course, you would cry at the lack of mastery of grammar and spelling, let alone physics.

Below I excerpt some depressing results from researchers at Stanford and Yale, which support the sorting and signalling model of higher ed, rather than the human capital building model.

Education and Verbal Ability over Time: Evidence from Three Multi-Time Sources

Nie, Golde and Butler

Abstract: During the 20th century, there was an unprecedented expansion in the level of educational attainment in America. Using three separate measures, this paper investigates whether there was a concurrent increase in verbal ability and skills. Changes in verbal ability in the general population as well as changes in the verbal ability of graduates of different levels of education are investigated. An additional investigation of how changes in the differences between males’ and females’ educational attainment are associated with changes in differences between their respective verbal abilities follows. The main finding is that there is little evidence that the large increase in educational attainment has resulted in an increase in any of the measures of verbal abilities and skills.

From the paper:

The results from using these three different measures of verbal ability and skills all show the same striking patterns: (1) there is no increase in scores in the overall population over time; (2) as the number of people obtaining a certain level of education increased, the verbal ability of those terminating with that degree has decreased. …

Comment for the psychometric cognoscenti: where is the Flynn effect here? I see no overall increase in verbal IQ.

See also this less technical exposition:

Nie and Golde: …Our initial hypothesis was that if amount of schooling causally affects any outcome, it would be verbal ability. The vast expansion of the American education system over the course of the 20th century served as our test bed. We expected that the huge increase in educational attainment in the U.S. across the decades would be accompanied by a substantial improvement in verbal abilities. To our initial amazement, we found no evidence for such improvement.

We started our investigation by showing that there is, indeed, a strong correlation between education and verbal ability. The data on which our analyses are based came from the General Social Survey, a program of in-person interviews that has been conducted regularly since 1972 by the National Opinion Research Center at the University of Chicago. While the samples were nationally representative, to avoid complications caused by changing demographics and questions about the validity of such tests with minority and immigrant populations, we included only the native-born, white American population 30 to 65 years of age, using information collected over the last 35 years of parallel surveys. (We used only those 30 years or older to ensure that we were dealing only with people who had completed their education; we stopped at age 65, lest we contaminate the analysis by differential mortality rates.)

Education levels and scores on a vocabulary test given to subjects are indeed correlated (see Figure 1). Over the three-plus decades studied, those with more education got better vocabulary scores, and vice versa.

Those results, however, do not necessarily imply that education causes increased verbal ability. If education did increase verbal ability, we would expect increasing levels of education over time to bring about measurably higher levels of verbal ability. During the 20th century, there was an unprecedented expansion in the levels of educational attainment in the U.S. The average American born between 1910 and 1914 received a bit more than 10 years of education. The average American born between 1970 and 1974 received 14 years of education. In 60 years, the “average American” went from being a high school dropout to having two years of college — a remarkable increase. The increase in education is across the board. A person born between 1910 and 1914 who obtained some postgraduate education was in the top 6 percent of his or her cohort in terms of education. By the 1970s, nearly 16 percent of the birth cohort had some postgraduate education. The percentage of college graduates or beyond has almost quadrupled over the same period, from just over 10 percent to almost 40 percent.

But, as Figure 2 shows, even though education has increased considerably through the decades, and even though education is correlated with verbal ability, verbal ability has stayed practically constant over time. The lack of change in the average vocabulary score of Americans, despite the large increase in the population’s average years of schooling, is an intriguing finding. …

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June 28, 2008 at 2:51 pm

Women in the classroom

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Interesting comments from Judith Warner of the Times, as she reports on a brain science workshop for journalists, held at MIT. The audience was more engaged (less intimidated?) by female lecturers. I find as well that women are less likely to try to get by with “proof by intimidation” than men, and that their presence tends to improve the quality of scientific discussion, assuming an equal level of competence.

Anyone familiar with Feynman idolatry knows that “man crushes” are just as real as what is described below for women.

At M.I.T., we were mostly spoken to by men, various kinds of men, of different ages and with different speaking styles, and we interacted with them with typical reportorial formality. Some were more popular with us than others; some were more engaged with us than others. Some spoke right over our heads; some reached even me with perfect clarity.

Something very different happened, however, on the two occasions when we were spoken to by women. The atmosphere in the room changed. We all became more familiar. We asked more questions. We interrupted more. We made sounds of assent or dissent; we questioned methods, concepts, base assumptions. It was as though, with the women, the boundaries dissolved. We were all immediately drawn into relationships.

How much of this had to do with the fact that the women tended to speak more relationally (“I think,” “I feel”), I don’t know. I don’t know if it was created by the fact that the women — to varying degrees — turned the story of their work into personal narratives.

I know that there was no conscious desire on anyone’s part to talk back to them or treat them with less respect. But one woman in particular, Rebecca Saxe, a young, dynamic professor of neurobiology at M.I.T. who gave a riveting presentation on social cognition — “how we reason about the desires and intentions that motivate others’ actions” — was interrupted so much by her super-engaged audience that she didn’t have time to get through essential portions of her talk.

I did not ask questions of this amazing young woman. I was struck, once again, with one of my crippling bouts of shyness, and besides that, I was too busy writing down her every word and wondering why on earth I had never taken science and whether my daughters might attend M.I.T.

Maybe I could send them to do summer study, I thought. (Once they’d both learned their multiplication tables, of course.) Maybe I should sport little wire glasses and wear my hair in a long braid. Or buy Birkenstocks.

“What did you think?” I breathed to a fellow female fellow, as we filed out of the classroom for lunch.

“I have a crush on her,” she said. The women around us made approving noises.

“It was her passion and energy and approach that was infectious,” she later explained in an e-mail. “I really had an emotional reaction to her, and found myself day dreaming about being her friend.”

What is this thing we so often do, when confronted with an impressive woman? Why do they, in particular, set off such a Pavlovian rush of emotion? Why, for women in particular, do they set off this me/not me engagement, this game of my friend/not my friend, this eternal, sometimes infernal play of positive or negative mirroring?

Men do a version of this with women, too — though I think it plays out more in terms of validates me/doesn’t validate me, which may amount, in slightly altered form, to much the same thing. I don’t see them doing it with other men. I don’t hear of men getting “crushes” on other men because they’re impressed with them. They don’t seem to get so flooded with the desire to be them, to try on their skins; they don’t appear to be constantly testing their identities against another man’s example, calling into question, at the drop of a hat, their clothing style or hair or general sense of being in the world.

Written by infoproc

June 27, 2008 at 5:37 pm

Posted in gender, science

What’s your social status?

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Calculate your social status using this tool from the NY Times. (Click on the components of class tab.) The inputs are occupation, education level, income and wealth. The tool was created to run with a week long series of articles on class in America, back in 2005.

Amazingly, my result is 95 (averaged over the 4 inputs), despite being pulled down by the occupational prestige score 82 of astronomers and physicists 🙂 We’re ranked number 5 overall out of several hundred occupations listed, with doctors and lawyers 1-2, and, strangely, database and system administrators 3-4. CEOs are way down at 46!

While social status can be crudely modeled by the average of the percentile results from the four inputs (higher average = higher social status), the figure doesn’t actually represent the percentage of the population with lower status, since the four inputs are correlated and the score assigned to occupation isn’t really a population percentile.

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June 26, 2008 at 11:41 pm

What’s your social status?

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Calculate your social status using this tool from the NY Times. (Click on the components of class tab.) The inputs are occupation, education level, income and wealth. The tool was created to run with a week long series of articles on class in America, back in 2005.

Amazingly, my result is 95 (averaged over the 4 inputs), despite being pulled down by the occupational prestige score 82 of astronomers and physicists 🙂 We’re ranked number 5 overall out of several hundred occupations listed, with doctors and lawyers 1-2, and, strangely, database and system administrators 3-4. CEOs are way down at 46!

While social status can be crudely modeled by the average of the percentile results from the four inputs (higher average = higher social status), the figure doesn’t actually represent the percentage of the population with lower status, since the four inputs are correlated and the score assigned to occupation isn’t really a population percentile.

Written by infoproc

June 26, 2008 at 11:41 pm

What’s your social status?

leave a comment »

Calculate your social status using this tool from the NY Times. (Click on the components of class tab.) The inputs are occupation, education level, income and wealth. The tool was created to run with a week long series of articles on class in America, back in 2005.

Amazingly, my result is 95 (averaged over the 4 inputs), despite being pulled down by the occupational prestige score 82 of astronomers and physicists 🙂 We’re ranked number 5 overall out of several hundred occupations listed, with doctors and lawyers 1-2, and, strangely, database and system administrators 3-4. CEOs are way down at 46!

While social status can be crudely modeled by the average of the percentile results from the four inputs (higher average = higher social status), the figure doesn’t actually represent the percentage of the population with lower status, since the four inputs are correlated and the score assigned to occupation isn’t really a population percentile.

Written by infoproc

June 26, 2008 at 11:41 pm