Archive for the 'Empirical Puzzles' Category

Post-Halloween Mystery

So apparently there was this pumpkin……

A colleague spotted it on the floor in front of my office door on Sunday afternoon and was intrigued enough (or weirded out enough) to snap a couple of pictures:

Unfortunately, by the time I came into work on Monday, the pumpkin had mysteriously disappeared. And I didn’t cross paths with my colleague until late this afternoon, which is when I first learned that there had ever been a pumpkin.

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Jobbing Between Two Lives

cadWhen the Greek goddess Hera wanted to know who enjoys sex more, men or women, she had the good sense to ask Tiresias, who had lived as both. (She did not, however, have the good sense to accept Tiresias’s answer).

When sociologist Kristen Schilt wanted to know why men and women succeed differently in the workplace, she had the good sense to ask workers who have lived as both. I’ve read only a fraction of Schilt’s book, but I learned a little about it from Jessica Nordell’s thoughtful writeup in the New Republic. The upshot seems to be that when women become men, they feel that they’re taken more seriously, whereas when men become women, they feel the opposite.

As Nordell points out, this really is a cool idea because a change in gender doesn’t change your skills or education, so when we track people’s experiences before and after their crossings, we’re holding a lot of relevant variables constant.

On the other hand, as Nordell also points out, there’s at least one important variable that’s not being held constant, and that’s testosterone level. When you go from female to male, you acquire a lot of testosterone; when you go from male to female you give up a lot. That opens up a lot of possibilities. Maybe testosterone makes you more effective at work, which leads to better treatment. Or maybe the treatment doesn’t change at all, but your testosterone level leads you to perceive it differently. (Likewise, of course, for a variety of other hormones.)

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This blows me away:

Suppose you pay children in the 5th and 6th grades, right when you think of the achievement gap opening up between blacks and whites, to take an IQ test.

Say you have unmotivated black kids living in the middle of the ghetto and white kids from Scarsdale or some other upper-class neighborhood. You give each kid who gets a successful answer one M&M — just give them an M&M — and you say for each point extra on the IQ test, each correct answer, I’ll give you one more M&M. It turns out that the gap between the black and white student in the IQ test scores vanishes — vanishes completely.

If I’d heard this from almost anyone else, I’d be instantly skeptical. But I heard it from Jim Heckman, who sets the standard for caution and reliability in social science. I highly recommend the whole interview; you can read it here.

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You Pays Your Money…..

A few months ago, I sat in a Dutailier glider and discovered that I had lived half a century with no concept of how comfortable a chair can be. My wife had exactly the same reaction. So we’d like to buy a couple of those chairs.

Unfortunately, Dutailier no longer makes the model we sat in. Fortunately, they make similar models. Unfortunately, they make one hundred and thirty nine models, of which at least fifty-nine appear to be serious contenders for “model most similar to the one we sat in”.

Those customers who somehow manage to choose among these models are then offered a choice of 113 different upholstery fabrics, 22 different wood finishes, and 10 “model options” (including “glide only”, “glide plus multiposition lock”, “glide plus autolock” and “glide plus multiposition lock plus autolock”) for a staggering 3,455,540 possible chairs. (That’s an approximation, because some models come with more or fewer options.) Color me paralyzed.

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Enough Already!

Today’s email brings a gripe from Mark Skousen, the irrepressible impresario behind FreedomFest, who could have avoided this problem by being born in the old Soviet Union:

I was in the large Stop & Shop grocery store here in New York to buy some items, including a new tube of toothpaste. I like Colgate, but I can never seem to get the same toothpaste product.

Now I know why. Guess how many different types and sizes of toothpaste Colgate sells?


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Thursday Riddle

Do any of you guys know anything about economics? Because I have a question I can’t answer and I’m hoping you can help me.

In many real estate markets (including the one where I’m currently shopping), the agent’s commission is equal to a fixed percentage of the sale price. (Typically it’s 6%, though this is split evenly between the buyer’s and seller’s agents, each of whom gives a cut to their respective agencies, so either agent’s take-home is more on the order of 2%).

This means that if you sell a million-dollar house, you earn TEN TIMES the commission of your identical twin who sold a hundred-thousand-dollar house, though I doubt very much that you did ten times the work or bore ten times the expense.

Now, plenty of hundred-thousand-dollar houses are being sold, which means that plenty of agents are settling for the relatively dinky commissions. Question: Why are those agents not attempting to steal some of the high-end business by offering to accept a smaller percentage? After all, 1% of a million is still a lot more than 2% of a hundred thousand.

You might say that the agencies collude to restrain them — but what stops a rogue agency from busting the cartel?

All too many times in my life, I’ve noticed some apparently anomalous behavior which I’ve challenged myself and/or others to explain with the tools of game theory, axiomatic bargaining theory, and the theory of markets — only to discover that the true explanation is “It’s required by law”. (Of course one can always step a little further back and try using economics to explain the advent of the law.) But I don’t think that’s the case here. (I’m prepared to be wrong about this, though.)

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The Economics of Teenage Pregnancy

Teenage motherhood is well correlated with poor economic outcomes. This of course need not mean that teenage motherhood causes poor economic outcomes; in fact, Melissa Kearney and Phillip Levine (of U. Maryland and Wellesley College) argue precisely the opposite: Being on a low economic trajectory causes teenage motherhood, and conditional on that original trajectory, teenage motherhood does little economic harm:

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Who Expected THAT?

Suppose you go around taking extremely close-up black-and-white pictures of randomly chosen natural and unnatural objects (rocks, trees, streams, buildings, etc.). What do they look like?

Well, each one looks like a patch of varying shades of gray, of course. But do some patches arise more than others? If each of your close-ups is, say, three pixels by three pixels, Which would you expect to see more of:

This? Or this?

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Why Jews Don’t Farm

I’ve been a little swamped lately and my daily blogging has fallen off. Until things get back to normal, I think I’ll fill the breach by reprinting a few of my old columns from Slate. Today’s entry is on “Why Jews Don’t Farm”.


In the 1890s, my Eastern European Jewish ancestors emigrated to an American Jewish farming community in Woodbine, N.J., where the millionaire philanthropist Baron de Hirsch provided land, tools, and training at one of the nation’s first agricultural colleges. But within a generation, the family had settled in Philadelphia where they became accountants, tailors, merchants, and eventually, lawyers and college professors.

De Hirsch had a vision of American Jews achieving economic liberation by working the land. If he’d had a better sense of history, he would have built not an agricultural college but a medical school, because for well over a millennium prior to the settlement of Woodbine, Jews had not been farmers—not in Palestine, not in the Muslim empire, not in Western Europe, not in Eastern Europe, not anywhere in the world.

You have to go back almost 2,000 years to find a time when Jews, like virtually every other identifiable group, were primarily an agricultural people. Around A.D. 200, Jews began to quit the land. By the seventh century, Jews had left their farms in large numbers to become craftsmen, artisans, merchants, and moneylenders—the only group to have given up on agriculture. Jewish participation in farming fell to about 10 percent through most of the world; even in Palestine it was only about 25 percent. Everyone else stayed on the farms.

(Even in the modern state of Israel, where agriculture has been an important component of the economy, it’s been a peculiarly capital-intensive form of agriculture, one that employed well under a quarter of the population at the height of the Kibbutz movement, and less than 3 percent of the population today.)

The obvious question is: Why? Why did Jews and only Jews take up urban occupations, and why did it happen so dramatically throughout the world? Two economic historians—Maristella Botticini (of Boston University and Universitá di Torino) and Zvi Eckstein (of Tel Aviv University and the University of Minnesota)—have recently been giving that question a lot of thought.

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How to Fix Everything

Here is how I answered that question in Jamaica:

Get the Flash Player to see this content.

(Slightly higher quality video here.)

Edited to add: There were apparently some problems with the video stalling somewhere around the one-hour mark (during the post-talk question period.) I believe this is fixed now.

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The High Price Of Wi-Fi

routerOne of my weaker columns when I wrote for Slate was a highly unsatisfactory stab at why some hotels charge for wireless and others don’t. Today my wife, who had never seen that column, asked me the same question, and I think my off-the-cuff answer was probably better than anything I said in Slate.

So here’s my new stab at this:

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Bars Versus Churches

Tyler Cowen asks: What variable best predicts your number of sex partners? My answer, which I stand by, was that it’s the same variable that best predicts your number of tennis partners, your number of checkers partners, and your number of visits to Disneyland — namely preferences. But Jason Malloy of Gene Expression steps in with something a little more empirically verifiable. Drawing on data from the respected General Social Survey, he’s correlated number of partners with everything from patriotism to empathy to “ever been punched” (all self-reported), and has invited me to share his results with you. Number of sex partners (also self-reported) is defined as number of partners since your 18th birthday. Jason’s calculations are restricted to heterosexual couplings. A negative number means that that a high response to the variable predicts fewer sex partners and a positive number means that a high response predicts more.

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Psychology Yesterday: Daughters and Divorce

slateboygirlBack in 2003, I reported (here, here and in more detail here) that in disparate cultures around the world, from the U.S. to Kenya and from Mexico to Vietnam, parents of daughters are more likely to get divorced. This phenomenon, discovered by the economists Gordon Dahl and Enrico Moretti, is based on a sample size over 3 million and is therefore surely no coincidence.

After seven years, psychologist Anita Kelly, writing in Psychology Today (which might want to consider changing its name to Psychology Yesterday) has penned a response. She accurately summarizes the original argument:

Dahl and Moretti have summarized attempts to explain their facts as follows: Sons may either improve the quality of married life or worsen the pain of divorce (perhaps by becoming more distraught when the father leaves). Landsburg chooses the former explanation based on the fact that parents, on average, prefer having boys over having girls.

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