I don't know the answer either but will take a swipe at a couple of effects. Posner points out, both, that today's jobs require higher intellectual skills and that the high tech itself makes jobs a lot more simple. Note the grocery checker who once had to be fast on a keyboard and able to count change but now primarily swipes and listens for a beep or has lost her job entirely to a self-check-out lane.

Another facet is that due to mechanization, outsourcing, HiB's and immigrants of all types the need for employees is not as high as it was in the 60's -- 80's when welders, computer techs and many others typically learned their craft on the job. Today companies can insist on college or at least a tech certificate.

Also, whether true or not, the perception is that those with just a HS degree, and certainly those w/o HS are poor candidates for training. So companies tend to use BA or BS requirements as a cheap means of sorting prospective employees even though a top HS grad may be a better bet than a low performing college grad.

Interestingly all four of our military branches run their fairly technical enterprises by employing HS grads for 90% of its (non-officer) positions and accomplishes this by testing what they get to find those of mechanical aptitude, clerical ability, or the physical ability to walk long distances carrying a heavy pack. They train most to be contributing members of a team in six months or a year.

As an aside, I'm not sure this is ideal; in the US most new police officers have a college degree or attended an intensive police academy while we send new recruits armed to the hilt into countries they don't understand, often with less than a day of "teaching" them about the culture or history.

If we wanted to make our system more efficient it would seem that we could add some credibility to having graduated HS (or not) by offering certificates indicating a level of accomplishment in math, English, computer skills, etc that a prospective employer could trust across the nation.

The more women in college thing? Haven't they always tended to follow the paved pathway? Get the credentials, become a teacher, and these days a lawyer etc. and not drop out to join the military, become a heavy equipment operator, or go off to far away places as an oil patch boomer, or construction worker?

Prediction? Something soon changes. As boomers leave their posts by the millions, those in mid-stride have the opp to move up rapidly leaving manpower vacuums at all levels. Do our corpies fill these positions here and take up some of the training burdens, or as with an IBM branch, here., last week pack up and move to South America or somewhere else? Aaah, it was best of times and the worst of times. As always?

If it was cool to drive a GTO in 1960, it is today cool to go to college. The job market is so tight that getting a loan to go to college is easier than finding a job for some. Women do better in college b/c they are, dare I say it, smarter, and consciously or unconsciously, know that they still earn only 77 cents for every dollar a male earns notwithstanding credentials so they may have fear and survival instincts at play. Gloria Steinem has accurately pointed out that the media was thrilled that Hillary lost b/c the media likes to see women lose and men win...moreover they were unhappy that she didn't bow out immediately and took FOUR whole days to do so...had Hillary been a man a much lengthier exit would have been expected. You have probably noted that the females in a male's family frequently prod men to do well in academia. When I was in law school my male housemates had mothers who would cook for them, tend to their laundry needs, basically hover about to nurse their non academic needs. I still see this ... while scrubbing toilets in Denali NP to afford the opportunity to study wildlife biology and hike Alaska, the males expected the females to acquiesce to their needs and superiority, both consciously and unconsciously. I loved JP's use of "upper body strength, naturally" ... AS JP points out in "How Judges Think" (Harvard Press, 2008) turf wars abound in courts -- and, abound out of courts -- in classrooms, call centers, pharmaceutical sales teams, apartment complexes -- all about persons fuss for greater pay, prestige, respect, and responsiblity... and in college they are vying for the good grade and hopefully the good knowledge which translates into a good paycheck...This brings to mind James Galbraith's new book on pay inequality...great post. Thank you.

"some instances (such as financial risk taking) concentrating once there on academic performance, may not contribute a great deal."

Getting a bulge bracket/high-end job in finance requires nearly-perfect grades, often in a discipline (math, engineering) that is very rigorous; and even traditional finance undergraduate degrees are becoming highly-quantitative. Most of the other jobs you describe (upper-body strength, etc.) don't require college. I don't think explains the higher grades among females.

Women's increased performance in college makes perfect sense if they (a) are genetically superior learners then men in the information economy, at least on the mean (if not the variance) or (b) they expect (true or not) to experience discrimination on future jobs, and need to be over-educated relative to men to get the same income.

Women are outperforming the men? Yeah right. I'll believe that when I meet a woman who works in math or physics, software design or even cabinetmaking. When we see the second ever female international grandmaster in chess and when women start beating the guys in the spelling, geography, math and science bees.

In the meantime, I'd just like to meet a woman with whom I could have an intelligent conversation concerning economics or politics, a degree in which requires (sadly) nothing beyond baby math.

What happens if you adjust the women in college data for race? I expect black and hispanic women to have an advantage over their male counterparts. Just as, once upon a time, Irish immigrant women found it much easier to find employment in "polite" society.

Also middle and upper middle income parents send their children to college. These kids have advantages through connections that are often worth more then the college degrees they receive.

Next, families that used to push mostly sons to college now push all the kids in the family.

For example, great aunt had seven children, four boys and three girls. My aunt had come to this country as a young women and she was determined to educate all her children because, as she said, an education is an easy burden to carry through life.

But with regard to college, she felt that the family could only afford to send the boys to college. The boys would raise families and attract mates based on their earning potential. The girls would have less to gain from an education, so college for them was out.

Her four sons all completed college and had good corporate careers. Her oldest daughter was class valedictorian of her high school but did not go to college. The family did not see an easy way to finance the education nor were they sure of the value. Oddly enough, through a series of events, this daughter became a multimillionaire and has a net worth higher then all her brothers combined. But I don't think many families would make the choice based on gender alone today.

Next
I think Jack is partly correct in that employers want credentials that are only partly related to job duties. I fear many employers set higher then required credentials as a way to eliminate minority candidates. But I also hear employers claim that they fear hiring a candidate without credentials for fear that rejected minority candidates (without credentials) could sue.

I suppose one reason the returns for a college education increased is because the incomes for unskilled and semi-skilled workers have fallen. Also recent immigrants seem to have placed downward pressure on these wages.

For most people a college education does not make you an extremely intelligent person. But to employers it does show that you can begin and end a task with mild supervision. You took classes that you had little interest in, but completed the required tasks. College gives you some basic skills, but for most graduates it reflects a level of maturity and drive that employers require. These are attributes that the typical high school drop lacks.

Finally
I'm not sure that graduates of good vocational or trade programs wouldn't also see positive returns to education. After adjusting for family dynamics and social status, I would suspect they financially outperform their college bound contemporaries. Regretfully most vocational programs are increasingly the dumping ground for poor students that the schools have quit trying to educate. And the faculty in such programs are increasingly of poor quality.

Prof Posner doesn't seem to respond to comments, but I would be interested to know if the returns to a college education increased for non-marketable majors as well, such as liberal arts, humanities, english, etc. If increasing returns to education over the past generation are due to increasing human-capital productivity--then what are these non-marketable majors doing differently today? How is shakespeare different today vs 30 or 100 years ago?

I'd like to second Ryan's question, as I did for Prof. Becker.

It would be possible that the mediocre college graduate's returns to education to be negative, and yet for attendance rates to increase considerably.

The returns to entertainers are generally very weak outside of the top 1%, but those superstars continually pull new hopeful entrants into the field. Freakonomics suggests illegal drug sales operate much the same way. (I sometimes wonder if the legal field I have just entered bears some similarity to this model.)

While it's plausible returns to middle of the road college education are very low, it's not necessarily the case, and Posner rightfully suggests a high potential return from high quality community colleges. It'd be nice to know the data, though.

There may be one significant factor as to “why” women are become more dominate in colleges. That factor is culture. Women have been at a disadvantage for the last century (voting and employment rights not equal to men). Because of this, they have been taught that it’s a male dominated world (glass ceiling, etc.) and they need to work harder and smarter to catch-up. I think we are seeing the catch-up now and it’s a great thing to witness!

I'm sure that Gary Becker has already thought of this but I'd like to know: What percentage of make births graduate from high school compared to females?

Boys definitely drop out more often than girls, and are more likely to get murdered or killed in a nonmurder scenario (e.g. killed by a cop, or in the military, or in a car accident, noting there is a good reason why auto insurance rates are higher for young males than females).

If there are 100 boys and 100 girls born in Beckerville 18 years ago and for one reason or another 50% (to pick a number out of a hat) of those boys don't graduate, while 10% of those girls don't graduate, and then 60% of the male graduates go on to college and 60% of the female graduates go on to college, then you get 54 girls and 30 boys starting Freshman class in 2008.

Same percentage of graduates in that scenario go on to college, but colleges receive many more girls than boys. So again, how much of the differential in male/female college entrances is due to different dropout rates and how much is due to choosing college over trades or the military or entrepreneurship?

Never underestimate the consumption aspect of higher education. In an affluent society, people can choose to grow up later.

jimbino, I just can't imagine why you haven't been able to find a woman to have an intelligent conversation with. What intelligent woman wants to talk to someone who believes that her intelligence makes her exceptional among her sex? The smart ladies are off talking to people who can manage to dial down the condescension and not draw unfounded conclusions from the uncontroversial observation that some abilities and skills are more prevalent among men and others among women.

Women’s superior performance in college may also be due to the fact that women generally care more than men about what others think about them. Thus they are more likely to care about what the professor wants them to learn rather than to focus on what they want to learn for themselves.