Category: Data Source

33 percent of the citizenry of the United Arab Emirates is clinically obese.

17 percent of the citizenry has diabetes.

The new energy bill will give us an extra hour of daylight savings time for parts of both March and November.  But is this a good idea?  Is daylight savings time at all a good idea?  I don’t know, but here is a new argument I never heard before:

“Springing forward” is tantamount to imposing a mild case of jet lag throughout the country, with potentially unhappy consequences.

Might that mean more traffic accidents?

…following the spring shift to Daylight Savings Time (when one hour of sleep is lost) there is a measurable increase in the number of traffic accidents that result in fatalities. Furthermore, it replicates the absence of any “rebound” reduction of accidents following the fall shift to DST (when the opportunity is present for an additional hour of sleep).

Of the two competing hypotheses for this increase in accidents, namely the one that suggests that it is the increased sleep deficit that causes the change in accident rate, versus notions based upon reduced illumination levels when driving to work, or suppositions that people forget the DST time change, fail to adjust their clocks, and find themselves rushing to work to avoid being late, the sleep hypothesis seems to be the most tenable. Hypotheses based upon haste and dim morning light both predict the bulk of the increased accidents to be confined to the morning hours. The sleep loss hypothesis would predict that individuals become more tired as the day wears on and hence the bulk of the accidents will appear later in the day. It is, of course, this latter pattern which appears with most of the accident fatality increase confined to the period after noon.

If the sleep loss hypothesis is correct, then why isn’t there a reduction in the number of traffic accidents in the fall, when the shift back to standard time provides an extra hour for sleep? Although this was the pattern observed in one study (Coren, 1996b) it has not replicated in other studies. The failure of the “safety rebound” may simply have to do with human nature. Just because a person has the opportunity to sleep for an addition hour does not mean that people actually will go to sleep on time. Many may spend that extra hour socializing or watching television. In some instances, where individuals do go to bed at the appropriate time, their usual circadian rhythm may still wake them after 7 or 8 hours in response internal signals or the external morning increase in illumination. Contrast this to what happens in the spring, where an individual’s work schedule will enforce the person’s awakening on the new DST time in order to meet job commitments.

Here is a blog post (with further discussion) on the topic, here is the underlying study, the original tip is from Eric Rasmusen.  I have yet to see data on whether Indiana — which does not adopt Daylight Savings Time — is in fact a safer place to drive, at least for a part of each year.

Consider the four square feet immediately around you. Now consider that are you occupying your average per capita share of the Great American Self Storage Empire. According to the Self Storage Association, a trade group charged with monitoring such things, the country now possesses some 1,875 billion square feet of personal storage. All this space is contained in nearly 40,000 facilities owned and operated by more than 2,000 entrepreneurs, including a handful of publicly traded giants like Public Storage, Storage USA, and Shurgard.

What this translates into, apart from one hell of a lot of stationary bikes kept behind padlocked metal doors, is an industry that now exceeds the revenues of Hollywood (and doesn’t have to deal with Tom Cruise). One in 11 American households, according to a recent survey, owns self-storage space–an increase of some 75 percent from 1995. Most operators of self-storage facilities report 90 percent occupancy, with average stints among its renters of 15 months. Last year alone saw a 24 percent spike in the number of self-storage units on the market.

The causes?  Lots of moving, ebay sellers, massive spending on large consumption goods, and smaller (or absent) attics and basements in many new homes.  Here is the full story.

We collected data on over 1000 taxicab rides in New Haven, CT in 2001. After controlling for a host of other variables, we find two potential racial disparities in tipping: (1) African-American cab drivers were tipped approximately one-third less than white cab drivers; and (2) African-American passengers tipped approximately one-half the amount of white passengers (African-American passengers are 3.7 times more likely than white passengers to leave no tip).

Many studies have documented seller discrimination against consumers, but this study tests and finds that consumers discriminate based on the seller’s race. African-American passengers also participated in the racial discrimination. While African-American passengers generally tipped less, they also tipped black drivers approximately one-third less than they tipped white drivers.

The finding that African-American passengers tend to tip less may not be robust to including better controls for passenger social class. But it is still possible to test for the racialized inference that cab drivers (who also could not directly observe passenger income) might make. Regressions suggest that a "rational" statistical discriminator would expect African Americans to tip 56.5% less than white passengers.

I’ve read the abstract but not yet the paper.  Note the authors wish to ban tipping [NB: they call it mandatory tipping] to limit racism.  Thanks to Mitch Berkson for the pointer.

Each year Slovakia produces about one car for each six citizens, of course mostly for export.  This is the highest such ratio in the world. 

See Business Week, 25 July 2005.

If Zambia had converted all the aid it received since 1960 to investment
and all of that investment to growth, it would have had a per capita GDP of about $20,000 by the early 1990s. Instead, Zambia’s per capita GDP in the early 1990s was lower than it had been in 1960, hovering under $500.

That is Bill Easterly, courtesy of Mahalanobis.  And did I mention that fifty years ago, South Korea had about the same standard of living?

Average percentage of the U.K. population that Britons believe to be immigrants: 21

Actual percentage: 8

That is from Harper’s Index, July 2005 issue.

In 1968, the number of pigs in China was 5.2 million; today it is 508 million. The number of poultry in China in 1968 was 12.3 million; today it is 13 billion.

Here is the story.  Yes this is great news, but it is also a reason why people are worried about China as a mixing bowl for an influenza pandemic.

Here is the link, thanks to Randall Parker for the pointer and commentary on the feasibility of wind power.  "Blue" is for superb conditions for wind power, and "red" is for outstanding, in case you can’t read the print on the chart.  And here is a wind map for the last six hours.

Grade inflation has not been constant through time.  Mark Thoma at Economist’s View offers some hypotheses.

There are two episodes that account for most grade inflation. The first
is from the 1960s through the early 1970s. This is usually explained by
the draft rules for the Vietnam War. The second episode begins around
1990 and is harder to explain….

My
study finds an interesting correlation in the data. During the time
grades were increasing, budgets were also tightening inducing a
substitution towards younger and less permanent faculty. I broke down
grade inflation by instructor rank and found it is much higher among
assistant professors, adjuncts, TAs, instructors, etc. than for
associate or full professors. These are instructors who are usually
hired year-to-year or need to demonstrate teaching effectiveness for
the job market, so they have an incentive to inflate evaluations as
much as possible, and high grades are one means of manipulating student
course evaluations.

But what are the consequences of grade inflation?  A new study takes advantage of a tres bon experiment.  In May of 1968 French students rioted, were suppressed by the police, but then joined by 10 million striking workers leading to a near revolutionary situation.  To quiet things down many students that year were accepted to universities which in former and later years they would not have qualified for.  What happened to those students?

Eric Maurin and Sandra McNally write:

We show that the lowering of thresholds at an early (and highly selective stage) of the higher education system enabled a significant proportion of students born between 1947 and 1950 (particularly in 1948 and 1949) to pursue more years of higher education that would otherwise have been possible. This was followed by a significant increase in their subsequent wages and occupational attainment, which was particularly evident for persons coming from a middle-class family background.  Finally, returns were transmitted to the next generation on account of the relationship between parental education and that of their children.

The results are surprising but consistent with Bowen and Bok who argue that affirmative action did not harm minority students who were accepted at universities at which they would not have qualified based on grades alone.

I’m puzzled but not yet ready to retire my reputation as a tough grader – my best students deserve no less.

Comments are open.

I’ll be spending this weekend on a mission to a Mexican mental hospital; I am helping a friend interview one of the patients, who is also an amate artist.  It is a respectable place, and provided they don’t confuse me with one of the inmates, I’ll have a good time.  I’ll be blogging from an Internet cafe in Cuernavaca and eating tamales in the street.

…the Guardian published what had until then been a government secret: which Brits rake in the biggest subsidies from the profligate European Union.  Near the top of the list was the queen herself, whose farm in Norfolk received 769,000 pounds (approximately $1.3 million) in 2003-4.

That is from the July issue of Reason magazine.  Here is the original story:

A spokesman for the Queen yesterday rejected any suggestion that she received too much money from the taxpayer. "The Queen is a landowner and a farmer. She receives subsidy, just as any other farmer would do."

The total would be higher if subsidies to Scotland — still a secret — were also included.

Perhaps the most pressing environmental problem in the world is indoor air pollution, which kills 2.8 million people each year, just behind HIV/AIDS.  The pollution is caused by poor people cooking and heating their homes with dung and cardboard.  The solution is not environmental (to certify dung) but rather economic, helping these people build enough wealth to afford kerosene.

That is by Bjorn Lomborg, in Foreign Policy, July/August issue. 

Two caveats.  First, the best figure I can find appears to be 1.6 million lives; here is a WHO statement on the phenomenon.  Second, the people die because the smoke renders them more susceptible to pneumonia and other respiratory diseases.  But their poverty makes them more susceptible for a number of reasons.  I doubt if the marginal product of the smoke can be isolated clearly; see this study.  Nonetheless this is a very very serious problem that does not receive much attention.

…two of the nation’s newspapers — The New York Times and The Wall Street Journal — are running extensive multipart series that paint a much darker picture.  The U.S., rather than being a land of opportunity, these stories argue, is increasingly a class-bound place of immobility and stratification, where it’s becoming ever harder for the people at the bottom to move up…

Rather than agonizing over relative comparisons, it may be better to concentrate on the simpler and intuitively satisfying concept of absolute "mobility," — whether you are doing better than your parents did, or whether the living standards of a whole group of people are rising over time.  From this perspective, there are signs that this past decade has had more upward mobility compared with the previous two decades…

There’s yet another big problem: we actually know very little about whether relative mobility increased or decreased during the New Economy decade because complete data don’t exist yet.  With a few exceptions, most studies stop with the mid- or late 1990s.

Here’s what we do know: Over the past decade, virtually every traditionally disadvantaged group made gains in absolute terms.  Take, for example, families headed by immigrants who entered the country in the 1980s.  The poverty rate for such families dropped sharply, from 26.6% in 1995 to 16.4% in 2003…Similarly, a combination of welfare reform and tight labor markets helped drive down the poverty rate for female-headed households with children from 46.1% in 1993 to 35.5% in 2003….it beats the total lack of progress in the previous decade.

That is from 20 June 2005, Business Week, by Michael Mandel.  Here is a new book on who gets ahead in low-wage labor markets.  Here is my previous post on Horatio Alger.  Here is my previous post on the family as a source of inequality.