Science

Further results on hypergamy

by on May 16, 2013 at 4:47 pm in Economics, Education, Science, Uncategorized | Permalink

This paper, by Marianne Bertrand, Jessica Pan, and Emir Kamenica, was pointed out by Matt Yglesias on Twitter, the abstract is this:

We examine causes and consequences of relative income within households. We establish that gender identity – in particular, an aversion to the wife earning more than the husband – impacts marriage formation, the wife’s labor force participation, the wife’s income conditional on working, marriage satisfaction, likelihood of divorce, and the division of home production. The distribution of the share of household income earned by the wife exhibits a sharp cliff at 0.5, which suggests that a couple is less willing to match if her income exceeds his. Within marriage markets, when a randomly chosen woman becomes more likely to earn more than a randomly chosen man, marriage rates decline. Within couples, if the wife’s potential income (based on her demographics) is likely to exceed the husband’s, the wife is less likely to be in the labor force and earns less than her potential if she does work. Couples where the wife earns more than the husband are less satisfied with their marriage and are more likely to divorce. Finally, based on time use surveys, the gender gap in non-market work is larger if the wife earns more than the husband.

Their title is “Gender Identity and Relative Income within Households.”  There is a non-gated copy here.

92 comments

Attempted fish markets in everything, economies of scope edition

by on May 14, 2013 at 5:54 am in Economics, Science | Permalink

The headline is: “Desperately Seeking Cichlid: Fish Species Down to Last 3 Males, No Known Females.”

Once upon a time the Mangarahara cichlid (Ptychochromis insolitus) lived in a single habitat: a river in Madagascar from which the species gets its name. That river has now been dammed and the habitat has dried up. Today there are just three Mangarahara cichlids left—all males. Two reside at the Zoological Society of London’s (ZSL) London Zoo Aquarium; the third lives at the Berlin Zoo.

Although the species appears to be extinct in the wild, ZSL London Zoo hopes that somewhere, somehow a female or two might exist in private hands. “We are urgently appealing to anyone who owns or knows someone who may own these critically endangered fish, which are silver in color with an orange-tipped tail, so that we can start a breeding program here at the zoo to bring them back from the brink of extinction,” aquarium curator Brian Zimmerman said in a press release last week.

The zoo has already reached out to other facilities around the world, with no luck. Now the only hope lies in private aquarium owners, fish collectors and hobbyists who might see the zoo’s appeal and realize that they own a female cichlid. The zoo has even set up a dedicated e-mail address for anyone with information: fishappeal@zsl.org.

Of course you can’t count on the market alone, as there are cultural preconditions for cooperation:

…even if a female does turn up, breeding won’t be guaranteed. Zimmerman told the BBC News that the Berlin Zoo used to have a female that it had hoped to breed with its male. Instead, the male killed its potential mate. “It’s a fairly common thing with cichlids,” Zimmerman said.

We’ll see how the supply elasticity works out on this one…

For the pointer I thank Chris MacDonald.

18 comments

Jim Manzi on the Oregon Medicaid study

by on May 13, 2013 at 1:19 pm in Medicine, Science, Uncategorized | Permalink

Via Megan, here is an excellent discussion of the study, here is one excerpt:

In summary, based on statistically insignificant effects of coverage from the Oregon Experiment: (1) The effects that are closest to statistical significance are that coverage would increase the rate of smoking and damage the cardiovascular prognosis of sick people; (2) the best estimated net effect on total population cardiovascular health is extraordinarily tiny; (3) this effect would be achieved by making the sick sicker, while very slightly improving the health of already healthy people ; and (4) this effect is almost certainly unattractive on a risk-adjusted basis. This is not a series of effects that makes a very attractive argument for an increase in health from the experiment.

…When interpreting the physical health results of the Oregon Experiment, we either apply a cut-off of 95% significance to identify those effects which will treat as relevant for decision-making, or we do not. If we do apply this cut-off (as the authors did; as is consistent with accepted practice for medical RCTs; and as is what I believe to be a good way to make decisions based on experiments), then we should agree with the authors’ conclusion that the experiment “showed that Medicaid coverage generated no significant improvements in measured physical health outcomes in the first 2 years.” If, on the other hand, we wish to consider non-statistically-significant effects, then we ought to conclude that the net effects were unattractive, mostly because coverage induced smoking, which more than offset the risk-adjusted physical health benefits provided by the incremental utilization of health services.

Do read the whole thing, there are many more points of interest.  For instance “Almost half the people offered free health insurance coverage didn’t bother to send back the application to get it.”

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Advice for young researchers

by on May 8, 2013 at 8:55 am in Economics, Education, Science, Uncategorized | Permalink

From Andrew Oswald, via the excellent Angus:, here is the opening bit:

If everyone likes your work, you can be certain that you haven’t done anything important. Conflict and pain go with the territory –
that of changing how a profession thinks and furthering what we know about our world. The pressures on young researchers are to conform, to accept fashionable ways of analyzing problems, and above all to please senior professors and their own peers. Unfortunately this is bad for scientific progress.
The main difference between world-class researchers and sound researchers is not intellect; it is energy, single-mindedness, more energy, and the ability to withstand what will sometimes feel like never-ending disappointment, tiredness and psychological pain. Tenacity is almost everything.

28 comments

Pandemics and public goods, and why we are failing at both

by on May 5, 2013 at 3:47 am in Economics, Medicine, Science, Uncategorized | Permalink

Here is my latest New York Times column, which has a specific part on how to address pandemics and a more general section on the evolving role of government in American society.  In neither area are matters running especially well.

Here is one initial point, namely that it is difficult to commit to allow high prices upfront:

Research and development grants are a way to pay potential innovators up front — an important move, as an innovator can’t always charge high-enough prices for the value of its remedies when they’re actually needed.

That will lead to institutional failure, rooted in a mix of government and market failure.  Therefore other rewards are needed, since the prospect of high prices does not adequately motivate.  I thus call for some key drugs to be rewarded with prizes and for government to buy out the patent rights, if need be:

If anyone doubted a government pledge to pay big money for the rights to remedies, the patent’s value could be established by a competitive auction. Michael Kremer, a Harvard economics professor, outlined the procedure for such an auction in his research paper “Patent Buyouts.”

The larger problem is this:

OVER all, the American government seems to be turning its back on its traditional role of producing and investing in national public goods. If there is any consistent tendency in recent government spending, it is that spending on entitlements like Social Security and Medicare — which provide mostly private benefits — is rising and that investment and spending on national public goods is falling.

Do read the whole thing.  I also suggest that (non-paternalistic) public health could be a suitable health care issue for Republicans, who presumably should be looking for alternatives to the status quo.

There are by the way two points which did not make the final cut for reasons of space.  First, the current coronavirus in Saudi Arabia has not gone away as a source of potential problems.  Second, the Bush Administration (43) did take some notable steps to return vaccine capacity to the United States, through both regulatory forbearance and HHS procurement.  These are likely good policies since in a pandemic one cannot expect to rely on free international trade in a remedy but rather export controls are to be expected.

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Claims about time

by on May 4, 2013 at 5:25 pm in Books, Science | Permalink

Alan Lightman relates some ideas from the new Lee Smolin book:

He [Smolin] goes on to propose a variety of revolutionary ideas to codify further his notion of “real time.” In one, he suggests that every atom in the universe is causally connected to every other atom in the universe, no matter how many light-years away. According to his notion, the failure of standard quantum mechanics to predict the behavior of individual atoms arises from the fact that it does not take into account the vast numbers of interconnections extending across the universe. Furthermore, this picture of the cosmos requires an absolute time (in violation of relativity), which he calls “preferred global time.”

One of Smolin’s most astonishing ideas is something he calls the “principle of precedence,” that repeated measurements of a particular phenomenon yield the same outcomes not because the phenomenon is subject to a law of nature but simply because the phenomenon has occurred in the past. “Such a principle,” Smolin writes, “would explain all the instances in which determinism by laws work but without forbidding new measurements to yield new outcomes, not predictable from knowledge of the past.” In Smolin’s view such unconstrained outcomes are necessary for “real” time.

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Interpreting Statistical Evidence

by on May 2, 2013 at 7:31 am in Data Source, Economics, Science | Permalink

Betsey Stevenson & Justin Wolfers offer six principles to separate lies from statistics:

1. Focus on how robust a finding is, meaning that different ways of looking at the evidence point to the same conclusion.

In Why Most Published Research Findings are False I offered a slightly different version of the same idea

Evaluate literatures not individual papers.

SWs second principle:

2. Data mavens often make a big deal of their results being statistically significant, which is a statement that it’s unlikely their findings simply reflect chance. Don’t confuse this with something actually mattering. With huge data sets, almost everything is statistically significant. On the flip side, tests of statistical significance sometimes tell us that the evidence is weak, rather than that an effect is nonexistent.

That’s correct but there is another point worth making. Tests of statistical significance are all conditional on the estimated model being the correct model. Results that should happen only 5% of the time by chance can happen much more often once we take into account model uncertainty not just parameter uncertainty.

3. Be wary of scholars using high-powered statistical techniques as a bludgeon to silence critics who are not specialists. If the author can’t explain what they’re doing in terms you can understand, then you shouldn’t be convinced.

I am mostly in agreement but SW and I are partial to natural experiments and similar methods which generally can be explained to the lay public while other econometricians (say of the Heckman school) do work that is much more difficult to follow without significant background and while being wary I also wouldn’t reject that kind of work out of hand.

4.  Don’t fall into the trap of thinking about an empirical finding as “right” or “wrong.” At best, data provide an imperfect guide. Evidence should always shift your thinking on an issue; the question is how far.

Yes, be Bayesian. See Bryan Caplan’s post on the Card-Krueger minimum wage study for a nice example.

5. Don’t mistake correlation for causation.

Does anyone still do this? I know the answer is yes.  I often find, however, that the opposite problem is more common among relatively sophisticated readers–they know that correlation isn’t causation but they don’t always appreciate that economists know this and have developed sophisticated approaches to disentangling the two. Most of the effort in a typical empirical paper in economics is spent on this issue.

6. Always ask “so what?” …The “so what” question is about moving beyond the internal validity of a finding to asking about its external usefulness.

Good advice although I also run across the opposite problem frequently, thinking that a study done in 2001 doesn’t tell us anything about 2013, for example.

Here, from my earlier post, are my rules for evaluating statistical studies:

1)  In evaluating any study try to take into account the amount of background noise.  That is, remember that the more hypotheses which are tested and the less selection which goes into choosing hypotheses the more likely it is that you are looking at noise.

2) Bigger samples are better.  (But note that even big samples won’t help to solve the problems of observational studies which is a whole other problem).

3) Small effects are to be distrusted.

4) Multiple sources and types of evidence are desirable.

5) Evaluate literatures not individual papers.

6)  Trust empirical papers which test other people’s theories more than empirical papers which test the author’s theory.

7)  As an editor or referee, don’t reject papers that fail to reject the null.

95 comments

Hoarding and aesthetics

by on April 30, 2013 at 3:12 pm in Science, The Arts | Permalink

Here is an excerpt from an interesting piece by Bonnie Tsui, from Pacific Standard, I liked this excerpt:

…hoarders literally see and treat their stuff differently.  The physical world of hoarders…is much ore expansive than what the rest of us perceive, and is often free of the rules that we are wont to impose.  Even more intriguing, Frost told me that some of the neurological hallmarks of hoarding might indicate a giftedness in the aesthetic appreciation of the physical world, rather than pure illness.  One of his patients had a pile that built up in the middle of her dorm room over the course of a week; she started perceiving shapes, colors, and textures, and it became a work of art — something with aesthetic value.  “She couldn’t dismantle it, because that would destroy it,” Frost said.

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The life of an academic con man

by on April 27, 2013 at 3:26 am in Education, Science | Permalink

The key to why Stapel got away with his fabrications for so long lies in his keen understanding of the sociology of his field. “I didn’t do strange stuff, I never said let’s do an experiment to show that the earth is flat,” he said. “I always checked — this may be by a cunning manipulative mind — that the experiment was reasonable, that it followed from the research that had come before, that it was just this extra step that everybody was waiting for.” He always read the research literature extensively to generate his hypotheses. “So that it was believable and could be argued that this was the only logical thing you would find,” he said. “Everybody wants you to be novel and creative, but you also need to be truthful and likely. You need to be able to say that this is completely new and exciting, but it’s very likely given what we know so far.”

Here is more, interesting throughout.  I liked this part too:

Stapel did not deny that his deceit was driven by ambition. But it was more complicated than that, he told me. He insisted that he loved social psychology but had been frustrated by the messiness of experimental data, which rarely led to clear conclusions. His lifelong obsession with elegance and order, he said, led him to concoct sexy results that journals found attractive. “It was a quest for aesthetics, for beauty — instead of the truth,” he said. He described his behavior as an addiction that drove him to carry out acts of increasingly daring fraud, like a junkie seeking a bigger and better high.

One of the best articles I’ve read this year, the author is Yudhijit Bhattacharjee.

42 comments

Are the empathetic dogs also the deceptive dogs?

by on April 24, 2013 at 2:54 am in Science | Permalink

That is one recent hypothesis which has come out of the “Dognition” program:

“One hypothesis has already emerged from Dognition’s users, Dr. Hare said. A surprising link turned up between empathy in dogs and deception. The dogs that are most bonded to their owners turn out to be most likely to observe their owner in order to steal food. “I would not have thought to test for that relationship at Duke, but with Dognition we can see it,” said Dr. Hare.”

The article is here, and I thank Vic Sarjoo for the pointer.

10 comments

Who shares data?

by on April 18, 2013 at 3:53 am in Data Source, Economics, Science | Permalink

Perhaps I’ve linked to this before, I am not sure, but it is worth another look:

We provide evidence for the status quo in economics with respect to data sharing using a unique data set with 488 hand-collected observations randomly taken from researchers’ academic webpages. Out of the sample, 435 researchers (89.14%) neither have a data&code section nor indicate whether and where their data is available. We find that 8.81% of researchers share some of their data whereas only 2.05% fully share. We run an ordered probit regression to relate the decision of researchers to share to their observable characteristics. We find that three predictors are positive and significant across specifications: being full professor, working at a higher-ranked institution and personal attitudes towards sharing as indicated by sharing other material such as lecture slides.

That is from Patrick Andreoli Versbach and Frank-Müller Lange, with a thanks to Florens Sauerbruch for the pointer.

Here (via @autismcrisis) is a new paper by John Ioannidis and Chris Doucouliagos, “What’s to Know About the Credibility of Empirical Economics?”, possibly gated for you, here is the abstract:

The scientific credibility of economics is itself a scientific question that can be addressed with both theoretical speculations and empirical data. In this review, we examine the major parameters that are expected to affect the credibility of empirical economics: sample size, magnitude of pursued effects, number and pre-selection of tested relationships, flexibility and lack of standardization in designs, definitions, outcomes and analyses, financial and other interests and prejudices, and the multiplicity and fragmentation of efforts. We summarize and discuss the empirical evidence on the lack of a robust reproducibility culture in economics and business research, the prevalence of potential publication and other selective reporting biases, and other failures and biases in the market of scientific information. Overall, the credibility of the economics literature is likely to be modest or even low.

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One further thought on the Reinhart and Rogoff fracas

by on April 17, 2013 at 12:41 pm in Economics, Science | Permalink

There is a genuine tension between becoming (and staying) “famous” and expressing all the appropriate levels of agnosticism on issues, which fairly often ought deserve quite an extreme agnosticism (see Mark Thoma on this).  It is hard to do both, and you can see this tension in the writings of most if not all well-known economists, at least in their more public pronouncements.  In the “good old days” that tension could be elided.  Academic discourse took place at relatively closed seminars, no quick responses were required, word traveled slowly, back and forth was much less rapid, and in general transparency was lower all around.

I’ve seen the Reinhart and Rogoff book in airports around the world, even though it is to most people unreadable or at best boring.  Could they have still made a splash if they had changed the title to This Time is Different: Why Inference from Macroeconomic Data is Really, Really Hard?  I don’t think so.

Enter the internet and the blogosphere.  Someone criticizes your work, in this case a body of work which has become very famous and made you very famous.  Do you respond by trying to defend the “fameworthiness” of the work, in which case a gross “rightness” might suffice, or at the very least you will try to outline the defensibility of your position.  Or do you respond by spelling out all of the reasons why one might be agnostic about a difficult issue?

I predict that most famous people will respond by trying to defend the fameworthiness of their work.

We as readers then respond by taking media which produce both fame and transparency — the internet and the economics blogosphere and Twitter — and suddenly wielding them as a weapon for transparency alone.  Obviously something won’t look right.  I don’t want to conclude “the fault is ours,” but it is still worth noting the tension between the mediums we patronize and what they are, to the broader world, actually good for.  It’s as if you showed up to Justin Bieber’s birthday party and started complaining that not everyone in the room deserves to be there.  They probably don’t, and their presence at the party should not cause you to overlook their shortcomings.  Still, it’s also good to be self-aware about one’s own role in uttering such a complaint about the quality of the party.

If you are receiving any public recognition at all, choosing how to present your material is one of the most difficult decisions.

Justin Fox has very good related comments.

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Absurd pitches (pull out the Hayek and Polanyi lesson)

by on April 17, 2013 at 7:37 am in Science, Web/Tech | Permalink

  • Facebook - the world needs yet another Myspace or Friendster except several years late. We’ll only open it up to a few thousand overworked, anti-social, Ivy Leaguers. Everyone else will then join since Harvard students are so cool.
  • Dropbox - we are going to build a file sharing and syncing solution when the market has a dozen of them that no one uses, supported by big companies like Microsoft. It will only do one thing well, and you’ll have to move all of your content to use it.
  • Amazon - we’ll sell books online, even though users are still scared to use credit cards on the web. Their shipping costs will eat up any money they save. They’ll do it for the convenience, even though they have to wait a week for the book.
  • Virgin Atlantic - airlines are cool. Let’s start one. How hard could it be? We’ll differentiate with a funny safety video and by not being a**holes.
  • Mint - give us all of your bank, brokerage, and credit card information. We’ll give it back to you with nice fonts. To make you feel richer, we’ll make them green.
  • Palantir - we’ll build arcane analytics software, put the company in California, hire a bunch of new college grad engineers, many of them immigrants, hire no sales reps, and close giant deals with D.C.-based defense and intelligence agencies!
  • Craigslist - it will be ugly. It will be free. Except for the hookers.
  • iOS - a brand new operating system that doesn’t run a single one of the millions of applications that have been developed for Mac OS, Windows, or Linux. Only Apple can build apps for it. It won’t have cut and paste.
  • Google - we are building the world’s 20th search engine at a time when most of the others have been abandoned as being commoditized money losers. We’ll strip out all of the ad-supported news and portal features so you won’t be distracted from using the free search stuff.
  • Github - software engineers will pay monthly fees for the rest of their lives in order to create free software out of other free software!
  • PayPal - people will use their insecure AOL and Yahoo email addresses to pay each other real money, backed by a non-bank with a cute name run by 20-somethings.
  • Paperless Post - we are like Evite, except you pay us. All of your friends will know that you are an idiot.
  • Instagram - filters! That’s right, we got filters!
  • LinkedIn - how about a professional social network, aimed at busy 30- and 40-somethings. They will use it once every 5 years when they go job searching.
  • Tesla - instead of just building batteries and selling them to Detroit, we are going to build our own cars from scratch plus own the distribution network. During a recession and a cleantech backlash.
  • SpaceX - if NASA can do it, so can we! It ain’t rocket science.
  • Firefox - we are going to build a better web browser, even though 90% of the world’s computers already have a free one built in. One guy will do most of the work.
  • Twitter - it is like email, SMS, or RSS. Except it does a lot less. It will be used mostly by geeks at first, followed by Britney Spears and Charlie Sheen.

That is all from Quora, hat tip goes to James Crabtree.

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*Political Arithmetic*

by on April 9, 2013 at 11:38 am in Books, Economics, History, Science | Permalink

The authors are Robert Fogel, Enid M. Fogel, Mark Guglielmo, and Nathaniel Grotte, and the subtitle is Simon Kuznets and the Empirical Tradition in Economics, on target as one might expect.

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“What’s the question about your field that you dread being asked?”

by on April 5, 2013 at 2:22 am in Economics, Science | Permalink

That is the new Edge symposium, with many excellent luminaries, including Jens Ludwig, Richard Thaler, and Raj Chetty from economics, with Sendhil Mullainathan playing host and interlocutor.  Chetty serves up these answers:

Here are three questions that come to mind that I dread answering as an economist working on policy issues:

1. If you were in charge, what policies would you enact today to raise growth rates and incomes for the average family in America?

2. Why do American students perform poorly relative to students in other countries and how can we fix education in the U.S.?

3. When are house prices going to recover to pre-recession levels?

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