Results for “Tests”
771 found

At the Frontier of Personalized Medicine

In an essay on frighteningly ambitious startups Paul Graham writes:

…in 2004 Bill Clinton found he was feeling short of breath. Doctors discovered that several of his arteries were over 90% blocked and 3 days later he had a quadruple bypass. It seems reasonable to assume Bill Clinton has the best medical care available. And yet even he had to wait till his arteries were over 90% blocked to learn that the number was over 90%. Surely at some point in the future we’ll know these numbers the way we now know something like our weight. Ditto for cancer. It will seem preposterous to future generations that we wait till patients have physical symptoms to be diagnosed with cancer. Cancer will show up on some sort of radar screen immediately.

An amazing paper in the March 16 issue of Cell illustrates the frontier of what is possible. Geneticist Michael Snyder of Stanford led a team that sequenced his and his mother’s genome. Then, over a two year period they used blood and other assays to track in Snyder’s body transcripts, proteins and metabolites. In the process they generated billions of data points and were able to watch in near real-time what happened as Snyder’s body fought two infections and the surprising onset of diabetes.

From a writeup in Science Daily:

…”We generated 2.67 billion individual reads of the transcriptome, which gave us a degree of analysis that has never been achieved before,” said Snyder. “This enabled us to see some very different processing and editing behaviors that no one had suspected. We also have two copies of each of our genes and we discovered they often behave differently during infection.” Overall, the researchers tracked nearly 20,000 distinct transcripts coding for 12,000 genes and measured the relative levels of more than 6,000 proteins and 1,000 metabolites in Snyder’s blood.

…The researchers identified about 2,000 genes that were expressed at higher levels during infection, including some involved in immune processes and the engulfment of infected cells, and about 2,200 genes that were expressed at lower levels, including some involved in insulin signaling and response.

…The exercise was in stark contrast to the cursory workup most of us receive when we go to the doctor for our regular physical exam. “Currently, we routinely measure fewer than 20 variables in a standard laboratory blood test,” said Snyder, who is also the Stanford W. Ascherman, MD, FACS, Professor in Genetics. “We could, and should, be measuring many, many thousands.”

One side-note: the techniques that the authors use to analyze their time-series data seem (to me) to be behind the curve compared to the VARs used in econometrics. Impulse response functions are what they need! With applications from economics to medicine to marketing, the statistics of big data is the field of the future.

Addendum: Derek Lowe offers further thoughts and Andrew S. points us to this TED video on blood tests without needles.

Temporary vs. permanent increases in government spending

Not long ago Paul Krugman wrote:

To a first approximation, in other words, the effect of current fiscal policy — whether stimulus or austerity — an [on?] the actions of future governments is zero.

He makes further points at the link, although there is not a citation to the literature.  I thought we should look at the evidence a little more closely.  Some of it contradicts Krugman as read literally, though it is not all bad news for his larger point.

Here is an abstract from Brian Goff:

In spite of Peacock and Wiseman’s 1961 NBER study demonstrating the “displacement effect”, simplistic theoretical and empirical distinctions between temporary and permanent spending are common. In this paper, impulse response functions from ARMA models as well as Cochrane’s non-parametric method support Peacock and Wiseman’s conclusion by showing 1) government spending in the aggregate displays strong persistence to temporary shocks, 2) simple decomposition methods intended to yield a “temporary” spending series have a weak statistical foundation, and 3) persistence in spending has increased during this century. Also, as a basic “fact” of government spending behavior, the displacement effect lends support to interest group and bureaucracy models of government spending growth.

There is persistence to spending, although this study does not create a category for stimulus spending per se, however that concept might be defined.  The work of Robert Higgs also provides a clear look at ratchet effects on government spending, control, and regulation, although Higgs focuses on war rather than spending.  State governments also seem to exhibit a ratchet effect, whereby good times bring about permanently higher budgetary demands, if only through endowment effects, lock-in, and status quo bias.

That said, the federal debt/gdp ratio seems to show mean reversion, as does the measure of primary surplus.  That would mean that fiscally troubled situations are followed by improvements, though not necessarily from spending decreases.  In fact there has been  considerable reliance on a “growth dividend.”  And here is Henning Bohn from the QJE:

How do governments react to the accumulation of debt? Do they take corrective measures, or do they let the debt grow? Whereas standard time series tests cannot reject a unit root in the U. S. debt-GDP ratio, this paper provides evidence of corrective action: the U. S. primary surplus is an increasing function of the debt-GDP ratio. The debt-GDP ratio displays mean-reversion if one controls for war-time spending and for cyclical fluctuations. The positive response of the primary surplus to changes in debt also shows that U. S. fiscal policy is satisfying an intertemporal budget constraint.

In other words, we make up for first-temporary-then-permanent spending boosts by a mix of growth and higher taxes.  Krugman might well be happy with that scenario, but the data do show intertemporal interdependence for budgetary decisions, with a mix of persistence on one variable (spending) and mean-reversion on another (debt-gdp ratio).  And if you think a lot of government spending is inefficient, you should still be troubled by apparently “temporary” spending bursts.

As with much of macroeconomics, I would apply a good dose of agnosticism to these results (noting that agnosticism is not the same as assuming zero effect), but still the correlations are consistent with my intuitions more generally.

Price discrimination for higher ed *classes*

Faced with deep funding cuts and strong student demand, Santa Monica College is pursuing a plan to offer a selection of higher-cost classes to students who need them, provoking protests from some who question the fairness of such a two-tiered education system.

Under the plan, approved by the governing board and believed to be the first of its kind in the nation, the two-year college would create a nonprofit foundation to offer such in-demand classes as English and math at a cost of about $200 per unit. Currently, fees are $36 per unit, set by the Legislature for California community college students. That fee will rise to $46 this summer.

The classes would be offered as soon as the upcoming summer and winter sessions; and, if successful, the program could expand to the entire academic year. The mechanics of the program are still being worked out, but generally the higher-cost classes would become available after state-funded classes fill up. The winter session may offer only the higher-cost classes, officials said.

That is some premium for reading and writing!  The naive might have thought that would have been guaranteed.  The story is here and for the pointer I thank Robert Tagorda.

Walking Fast and Slow

In a famous paper psychologist John Bargh and collaborators gave students at NYU a test very similar to that described by Malcolm Gladwell in Blink:

In front of you is a sheet of paper with a list of five-word sets. I want you to make a grammatical four-word sentence as quickly as possible out of each set. It’s called a scrambled-sentence test. Ready?

  1. him was worried she always
  2. are from Florida oranges temperature
  3. ball the throw toss silently
  4. shoes give replace old the
  5. he observes occasionally people watches
  6. be will sweat lonely they
  7. sky the seamless gray is
  8. should not withdraw forgetful we
  9. us bingo sing play let
  10. sunlight makes temperature wrinkle raisins

The students were then sent to do another test in an office down the hall. Unbeknownst to them, walking the hall was the real experiment. Scattered in the sentences above are words like “worried,” “Florida,” “old,” “lonely,” “gray,” “bingo,” and “wrinkle.” Bargh reported that students who had been primed with these words took significantly longer to walk down the hall than those not primed with the “old” words.

In the original study there were only 60 participants and the subjects were timed with a stopwatch. A new paper doubles the sample size and uses more accurate infrared sensors. You will probably not be surprised to learn that the new paper fails to replicate the priming effect. As we know from Why Most Published Research Findings are False (also here), failure to replicate is common, especially when sample sizes are small. I haven’t yet described the real surprise, however.

The authors of the new paper, Doyen et al., then took the experiment meta; they ran the experiment again but this time they told half the people supposedly “running” the experiment that they expected the participants to walk slower and the other half they told that they expected the participants to walk faster. (A confederate provided evidence for this effect.) In the second experiment they again used the infrared sensors but they also asked the nominal experimenters to use a stopwatch as the sensors were said to be new and sometimes unreliable.

In the second experiment Doyen et al. were able to replicate the Bargh results. Namely, when using the stopwatch, the nominal experimenters reported that the group primed to walk slow did walk slow and they reported that the group primed to walk fast did walk fast. The results, however, were not entirely due to subtle experimenter bias because in the slow prime case the infrared sensors also found that the slow-primed group walked slow. The infrared sensors, however, did not report an increase in speed when the nominal experimenters expected an increase in speed.

Thus, the old-slow priming results appear to be due to a subtle mix of experimenter bias and standard priming which is cued or amplified via experimenter signaling. Given what are still relatively small sample sizes (50-60) the last should also be taken provisionally.

Important Addendum: Bargh has written a nasty attack on the new paper, the journal that published the paper, and Ed Yong who blogged the new paper for Discover Magazine. Bargh’s attack is a model of how not to respond to criticism new information. Ed Yong discusses Bargh’s response here. Like Yong, I am dismayed that Bargh quotes the new paper inaccurately. In his attack, Bargh also says things such as the overuse of elderly-related items reduces the effect of the prime. Yet in the methods paper he cites (and wrote) he says more prime stimuli generally results in bigger effects (p.11, effects can vary if the subjects consciously recognize the prime, a factor that the new paper tests). Bargh also entirely glosses over the main point which is that the authors did find priming effects when the experimenter knew and expected the effect to occur. Note that given the subtlety of the effects any experimenter bias appears to be entirely unintentional and Doyen never argue otherwise.

Charles Murray’s policy proposals

To narrow the class divide, that is.  I am almost completely in disagreement (how about more aid and opportunity, less attempted equalization?), the Op-Ed is here.  In the form of a list:

1. Apply the minimum wage to internships for the young, so privileged children cannot so easily receive this training.

2. Replace the SAT with specific subject tests.

3. Replace ethnic affirmative action with socioeconomic affirmative action.

4. Sue to challenge the constitutionality of a B.A. degree as a job requirement.

He does admit these proposals will not do so much good in absolute terms, but he nonetheless praises them for their symbolic value.

There is no great stagnation

The drone of speakers who won’t stop is an inevitable experience at conferences, meetings, cinemas, and public libraries.

Today, Kazutaka Kurihara at the National Institute of Advanced Industrial Science and Technology in Tskuba and Koji Tsukada at Ochanomizu University, both in Japan, present a radical solution: a speech-jamming device that forces recalcitrant speakers into submission.

The idea is simple. Psychologists have known for some years that it is almost impossible to speak when your words are replayed to you with a delay of a fraction of a second.

Kurihara and Tsukada have simply built a handheld device consisting of a microphone and a  speaker that does just that: it records a person’s voice and replays it to them with a delay of about 0.2 seconds. The microphone and speaker are directional so the device can be aimed at a speaker from a distance, like a gun.

In tests, Kurihara and Tsukada say their speech jamming gun works well: “The system can disturb remote people’s speech without any physical discomfort.”

Their tests also identify some curious phenomena. They say the gun is more effective when the delay varies in time and more effective against speech that involves reading aloud than against spontaneous monologue. Sadly, they report that it has no effect on meaningless sound sequences such as “aaaaarghhh”.

Kurihara and Tsukada make no claims about the commercial potential of their device but  list various aplications. They say it could be used to maintain silence in public libraries and to “facilitate discussion” in group meetings. “We have to establish and obey rules for proper turn-taking when speaking,” they say.

Here is more, and for the pointer I thank Michelle Dawson, here is her recent dialogue.

How good are the upper classes?

Seven studies using experimental and naturalistic methods reveal that upper-class individuals behave more unethically than lower-class individuals. In studies 1 and 2, upper-class individuals were more likely to break the law while driving, relative to lower-class individuals. In follow-up laboratory studies, upper-class individuals were more likely to exhibit unethical decision-making tendencies (study 3), take valued goods from others (study 4), lie in a negotiation (study 5), cheat to increase their chances of winning a prize (study 6), and endorse unethical behavior at work (study 7) than were lower-class individuals. Mediator and moderator data demonstrated that upper-class individuals’ unethical tendencies are accounted for, in part, by their more favorable attitudes toward greed.

That is an abstract from Paul K. Piff, Daniel M. Stancato, Stephane Coté, Rodolfo Mendoza-Denton, and Dacher Keltner.  There is a gated version of the paper here,  a Wired summary hereDozens of other sources covered the paper on-line but virtually all fell afoul of mood affiliation (something is wrong with the wealthy and here is a chance to disapprove of them), and a very large number made the subtle shift from “upper class” to “wealthy,” which of course is not the same.

We need to be cautious in our interpretation of these results.  Of the seven tests, two of them showed that people driving more expensive cars are more in a hurry and more likely to cut off others or not yield.  That’s not praiseworthy, but hardly a major moral condemnation.  Several of the tests involved people being asked to imagine they were high class, not actual “high class” people themselves.  To that extent we are testing the lower class view of the upper classes, noting that I would not use those terms as given.  One of the tests showed that social class did not matter once we adjust for a person’s attitude toward greed.   A positive attitude toward greed is positively correlated with social class, but it was also easy enough to “prime” the lower class individuals to feel the same way, suggesting that extreme context dependence will hold here.

Let’s view these results in light of the literature as a whole (I haven’t seen any journalistic source do this).  Very often in studies the highest trust, lowest corruption societies in the world are the relatively wealthy Nordic countries, not poor countries.  There is plenty of evidence that it is low and falling incomes — not wealth — which helped to explain voter support for fascism.  Consumers are eager to buy products from companies such as Apple, and they regard the wealth of the shareholders, and the high profit margins, as a sign they will get a high quality product, not a reason to fear a rip-off.  (Can you think of many cases where consumers deliberately seek out lower-class suppliers to minimize the chance of rip-off?)  The work of Garett Jones shows that high IQ predicts greater cooperativeness.

That all said, allow me to speculate.  If I were playing bridge, and my opponents were wealthy, I really would expect them to cheat more, say with regard to the exchange of illegal cues between partners.  For one thing cheating requires some smarts and for another it requires some confidence that it can lead to victory.  I expect Vlade Divac to flop more to draw a foul, or expect Kobe Bryant to work harder to manipulate a referee, than I would expect from a lower-status rookie player.

One simple hypothesis — which for now I will take as the default, when you sum up all the evidence — is that high-status people cheat more at games and less at many other activities, including those of real life.  (They are also in more of a hurry on the road.)  That’s very different than how this paper is being reported, and it’s also a much more interesting hypothesis.

Addendum: Kevin Drum comments.

Assorted links

1. New Carl Zimmer project on science eBook reviews.

2. Empirical tests of how much “cold start” is a problem in labor economics.  From this general blog on on-line labor markets and their implications.

3. Markets in everything: dog TV.

4. NYT symposium on the farm bill, including yours truly.

5. Whorfian economics.

6. CrookedTimber is running a symposium on Graeber’s debt book.

7. Early John Nash on cryptography, written to the NSA.

Charles Duhigg’s The Power of Habit

The skills necessary to ride a bike are multifaceted, complex and not at all obvious or even easily explicable to the conscious mind. Once you learn, however, you never forget–that is the power of habit. Without the power of habit, we would be lost. Once a routine is programmed into system one (to use Kahneman’s terminology) we can accomplish great skills with astonishing ease. Our conscious mind, our system two, is not nearly fast enough or accurate enough to handle even what seems like a relatively simple task such as hitting a golf ball–which is why sports stars must learn to turn off system two, to practice “the art of not thinking,” in order to succeed.

Habits, however, can easily lead one into error. In the picture at right, which yellow line is longer? System one tells us that the lhttp://i161.photobucket.com/albums/t225/SprinkleCoveredPocky/Optical%20Illusions/Illusion9.pngine at the top is longer even though we all know that the lines are the same size. Measure once, measure twice, measure again and again and still the one at top looks longer at first glance. Now consider that this task is simple and system two knows with great certainty and conviction that the lines are the same and yet even so, it takes effort to overcome system one. Is it any wonder that we have much greater difficulty overcoming system one when the task is more complicated and system two less certain?

You never forget how to ride a bike. You also never forget how to eat, drink, or gamble–that is, you never forget the cues and rewards that boot up your behavioral routine, the habit loop. The habit loop is great when we need to reverse out of the driveway in the morning; cue the routine and let the zombie-within take over–we don’t even have to think about it–and we are out of the driveway in a flash. It’s not so great when we don’t want to eat the cookie on the counter–the cookie is seen, the routine is cued and the zombie-within gobbles it up–we don’t even have to think about it–oh sure, sometimes system two protests but heh what’s one cookie? And who is to say, maybe the line at the top is longer, it sure looks that way. Yum.

System two is at a distinct disadvantage and never more so when system one is backed by billions of dollars in advertising and research designed to encourage system one and armor it against the competition, skeptical system two. Yes, a company can make money selling rope to system two, but system one is the big spender.

Habits can never truly be broken but if one can recognize the cues and substitute different rewards to produce new routines, bad habits can be replaced with other, hopefully better habits. It’s habits all the way down but we have some choice about which habits bear the ego.

Charles Duhigg’s The Power of Habit, about which I am riffing off here, is all about habits and how they play out in the lives of people, organizations and cultures. I most enjoyed the opening and closing sections on the psychology of habits which can be read as a kind of user’s manual for managing your system one. The Power of Habit, following the Gladwellian style, also includes sections on the habits of corporations and groups (hello lucrative speaking gigs) some of these lost the main theme for me but the stories about Alcoa, Starbucks and the Civil Rights movement were still very good.

Duhigg is an excellent writer (he is the co-author of the recent investigative article on Apple, manufacturing and China that received so much attention) It will also not have escaped the reader’s attention that if a book about habits isn’t a great read then the author doesn’t know his material. Duhigg knows his material. The Power of Habit was hard to put down.

The economics of higher non-profit and for-profit education

Here is a 2009 paper of mine with Sam Papenfuss (pdf), a later version of which was published in this book edited by Joshua Hall.  The paper deliberately sidesteps the recent scandals and focuses on fundamentalist explanations of why higher education might be provided on a non-profit or for-profit basis.

The key stylized facts are this:

Two primary features characterize the observed educational for-profits. First, for-profits tend to specialize in highly practical or vocational forms of training. For-profits are especially prominent in areas where student performance can be measured by a relatively objective, standardized test. Nonprofits, in contrast, have a stronger presence in the liberal arts, although they are by no means restricted to that arena..

This is a general pattern, and not unique to the United States today:

A comparison of for-profit and non-profit institutions in the Philippines [in the 1970s] bears out many of the differences noted above. Filipino for-profits tend to charge lower fees, specialize in education of lower academic reputation, spend less on capital equipment, and serve students who plan on pursuing vocational careers or taking a standardized vocational test upon graduation…Students at for-profits are approximately ten times more likely to take the tests. Adjusting for the lower pass rate from for-profits, the for-profits are putting about five times the number of students through the tests as the non-profits, even though for-profits educated no more than three-fifths of all Filipino students at the time.

Here is one possible (partial) resolution:

Faculty governance implies that for-profits and nonprofits place different relative weight on reputation and profits. The for-profit selects students and faculty on the basis of how easily their reputational benefits can be captured by shareholders, whereas the non-profit places greater weight on the reputational benefits that are kept by faculty. The for-profit pursues “reputation as valued by students in dollar terms” and the nonprofit pursues “reputation with the external world,” or “reputation as a public good.” In the resulting equilibrium, for-profits achieve lower status.

…The hypothesis therefore predicts a segmented market for higher education. Students who seek the highest levels of certification and reputation will attend non-profit institutions, which are run by faculty and use their prestige to raise donations. Students whose quality can be certified by an outside vocational exam do not need the non-profit reputational endorsement. They will pursue the more efficient instruction offered by for-profits.

There is a good recent paper by David Deming, Claudia Goldin, and Lawrence F. Katz on educational for-profits, available here.  Here is a 2010 Dick Vedder piece on for-profits, more positive than most recent accounts.

Sentences to ponder

…when Prime Minister Mario Monti remarked that having a job for life in today’s economy was no longer feasible for young people — indeed, it was “monotonous” — he set off a barrage of protests, laying bare one of the sacrosanct tenets of Italian society that the euro zone crisis has placed at risk.

Reaction was fast, furious, bipartisan and intergenerational. “I think the prime minister has to be careful with the words he uses because people are a little angry,” Claudia Vori, a 31-year-old Rome native who has had 18 different jobs since graduating from high school in 1999…

This point is not irrelevant:

Debate has been especially intense over Article 18 of the 1970 Workers Statute, which forbids companies with more that 15 employees from firing people without just cause. The unions say that line cannot be crossed.

The article is here.  How many years does it take to a) undo this, and b) have it kick in as a positive for growth?  This again also gets back to the question of why Germany does not wish to pay for everything.  By the way, is anyone writing a behavioral economics piece about how “crisis fatigue” increasingly is shaping eurozone policy?

Assorted links

1. There is no great stagnation, equine edition, the spread of finance, measuring worker value, and a metaphor for the American economy, all in one simple story.  Masterful.

2. English translation of an Adonis poem, from Syria.

3. What is the conditional probability of being struck by lightning?

4. Profile of Wendy Braitman, she was recently discussed (at length) in this links section.

5. Rabbit leaping contests are one thing.  Bevolke, please explain the Norwegian dog lockers.  It seems to be a design trend (?), more here.  Is it just Keynes chapter 17 all over again?  Are they air conditioned during the summer?  Need they be?

6. The velocity of guns is rising; of course that is contractionary in the macroeconomic sense.

These should keep you busy for a while.

Udacity

In The Coming Education Revolution I discussed Sebatian Thurn and Peter Norvig’s online AI class from Stanford that ended up enrolling 160,000 students. Felix Salmon has the remarkable update:

…there were more students in [Thrun’s] course from Lithuania alone than there are students at Stanford altogether. There were students in Afghanistan, exfiltrating war zones to grab an hour of connectivity to finish the homework assignments. There were single mothers keeping the faith and staying with the course even as their families were being hit by tragedy. And when it finished, thousands of students around the world were educated and inspired. Some 248 of them, in total, got a perfect score: they never got a single question wrong, over the entire course of the class. All 248 took the course online; not one was enrolled at Stanford.

Thrun was eloquent on the subject of how he realized that he had been running “weeder” classes, designed to be tough and make students fail and make himself, the professor, look good. Going forwards, he said, he wanted to learn from Khan Academy and build courses designed to make as many students as possible succeed — by revisiting classes and tests as many times as necessary until they really master the material.

And I loved as well his story of the physical class at Stanford, which dwindled from 200 students to 30 students because the online course was more intimate and better at teaching than the real-world course on which it was based.

So what I was expecting was an announcement from Thrun that he was helping to reinvent university education: that he was moving all his Stanford courses online, that the physical class would be a space for students to get more personalized help. No more lecturing: instead, the classes would be taken on the students’ own time, and the job of the real-world professor would be to answer questions from kids paying $30,000 for their education.

But that’s not the announcement that Thrun gave. Instead, he said, he concluded that “I can’t teach at Stanford again.” He’s given up his tenure at Stanford, and he’s started a new online university called Udacity. He wants to enroll 500,000 students for his first course, on how to build a search engine — and of course it’s all going to be free.

Might schooling raise IQ?

Children who have more schooling may see their IQ improve, Norwegian researchers have found.

Although time spent in school has been linked with IQ, earlier studies did not rule out the possibility that people with higher IQs might simply be likelier to get more education than others, the researchers noted.

Now, however, “there is good evidence to support the notion that schooling does make you ‘smarter’ in some general relevant way as measured by IQ tests,” said study author Taryn Galloway, a researcher at Statistics Norway in Oslo.

Findings from the large-scale study appear in this week’s online edition of the Proceedings of the National Academy of Sciences.

…In 1955, Norway began extending compulsory middle school education by two years. Galloway and her colleague Christian Brinch, from the department of economics at the University of Oslo, analyzed how this additional schooling might affect IQ.

Using data on men born between 1950 and 1958, the researchers looked at the level of schooling by age 30. They also looked at IQ scores of the men when they were 19.

“The size of the effect was quite large,” she said. Comparing IQ scores before and after the education reform, the average increased by 0.6 points, which correlated with an increase in IQ of 3.7 points for an addition year of schooling, Galloway said.

The summary is here, the paper is here, and for the pointer I thank Michelle Dawson.