The obvious and the obviously obvious

This quote (cited by Andrew Gelman via a badly chosen URL), "The necessary conceit of the essayist must be that in writing down what is obvious to him he is not wasting his reader’s time." got me to thinking about what we mean when we say "obvious" or, more precisely, the different things that different people mean when they use the word in different contexts.

The obvi-... er, first example that comes to mind is this anecdote I first encountered in The World of Mathematics."

A famous math professor was giving a lecture during which he said "it is obvious that..." and then he paused at length in thought, and then excused himself from the lecture temporarily. Upon his return some fifteen minutes later he said "Yes, it is obvious that...." and continued the lecture.

A slightly different form of this anecdote was cited by Paul Renteln and Alan Dundes in their essay on mathematical folklore, unfortunately, it seems fairly obv-... make that, fairly clear to me that they missed the point of the joke:

This metajoke says a lot about mathematicians. First, they are often very quick thinkers, able to reach conclusions far faster than others. Second, they can see the humor in some jokes but are easily bored by the routine or familiar. Third, they often dismiss results that are obvious to themselves as “trivial”, even though the results may not be trivial to others. The following joke vividly illustrates this penchant.

A mathematics professor was lecturing to a class of students. As he wrote something on the board, he said to the class “Of course, this is immediately obvious.” Upon seeing the blank stares of the students, he turned back to contemplate what he had just written. He began to pace back and forth, deep in thought. After about 10 minutes, just as the silence was beginning to become uncomfortable, he brightened, turned to the class and said, “Yes, it IS obvious.”

The problem with this interpretation is that the students' confusion is not only not a central feature of the joke; it's not even a standard element (note that it doesn't appear at all in the previous version).

The joke here isn't that what's obvious to a mathematician may not be obvious to mere mortals. Instead, it's the far more interesting point that mathematicians and their ilk (and if you're reading this...) often use the words like "obvious" in a way that, though relatively precise, is very different from the way normal people use them. In common usage, being obvious is itself obvious. Normal people sometimes wonder if something that seems obvious is really true but they never spend time wondering if something that is true is really obvious.

At the risk of speculating on the motives of the apocryphal (and keeping in mind that I haven't taken a pure math class in more than a decade), I'd say that 'obvious' in this context means 'does not require a lemma.' You will hear mathematicians use the word in this sense, even though the question of whether or not a proof is complete is often far from obvious inn the traditional sense.

You could make a similar point about the way economists use 'rational' but that's a topic for another post.

Weekend blogging -- TV spies and war games

I came across a Youtube channel dedicated to the late Sixties/early Seventies show Callan. In case you're not familiar with it, the show was basically British television's answer to The Spy Who Came in from the Cold and the other anti-Bonds of the period. It was also the role that brought Edward Woodward to prominence thanks to an extraordinary portrayal of a man eaten away with self loathing.

Callan lives a drab life and genuinely hates his work and most of the people he works with. The only consistent source of pleasure in his life is his collection of Napoleonic war game miniatures. Occasionally, stories revolved around actual gaming, like the episode, "Act of Kindness" from the third season.

Which is a pretty good excuse to post it as part of our ongoing gaming thread.

Other people get their allusions from classical literature; I use old Superbowl ads.

Like a lot of people, I've always looked at Grover Norquist as both dangerous and untrustwworthy. Certainly the last peerson I'd expect to balk at extremism, but recent events have made what were fairly fine distinctions plain. In the case of Norquist, this interview reminds us that even the hitchhiker with an axe draws the line at the one with the chainsaw.

Electronic currency

It seems like Bitcoin is experiencing a bit of a set-back.  It is probably not that surprising that such a strong challenge to fiat currency has been met by federal investigators.  The more high profile the challenge, the easier it would have been to meet it.  It is the stuff that isn't advertising on Wall Street that might slip under the radar.

Amazing sentence of the day

Wow, just wow:

They analyzed the results of 305 randomized controlled trials involving 339,274 individuals and found no statistically detectable differences between exercise and drug interventions for secondary prevention of heart disease and prevention of diabetes.

I plan to review the paper today but remember that randomization protects against many possible sources of bias.  It doesn't mean that these recommendations apply to all patients at all times, nor does it address the possibility of additive effects.  If you are thinking of changing your activity level it is prudent to discuss potential risks with your health care provider in advance.

But it makes it clear that we under-utilize a really remarkable treatment. 

Orthogonality in political debates

I think that I feel the most like an expat at times like this, when the American political elite are talking about the size of government.  I have always thought that the size of government was secondary to the quality of government.  The comparison between states like Sweden and Singapore suggests to me that well run governments can be an important part of a society, almost irrespective of size.  Obviously there are limiting factors at the extremes, but the general principle isn't far out of line. 

Now this isn't a "pox on both your houses" moment.  It's a question about whether we are having the correct conversation at all.  Now there has been some reporting on things like the computer websites for the Affordable Care Act and whether they are working well.  This is a much more interesting debate, as it gets to the heart of how government can be made to work better. 

Why isn't good government the priority? 

A problem of measurement

Trying to actually measure outcomes is a very tricky business when you are looking at things like educational outcomes.  It's harder when you have competing measures that you have to try and arbitrate between.  However, the worst possible way to deal with this type of measure is to only pick the one that best supports the story you want to tell. 

At a larger level, I would be interested in looking for ideas from countries that have higher ranks.  Finland, for example, seems to have been doing the opposite of the United States and seems to rank highly. 

Charter schools

Okay, this piece in Forbes about the money to be made in charter schools is really pointing out the potential hazards of these sorts of movements.  It is not that they can't necessarily improve outcomes (at least in a theoretical sense) but that there can be a lot of potential to shift the focus from educating students to making profits.  It is a classic principal agent situation as the person paying (the government) is not the person receiving the services (the students). 

Consider:

Nor does the evidence show that charters spend taxpayers’ money more efficiently. Researchers from Michigan State and the University of Utah studied charters in Michigan, finding they spent $774 more per student on administration, and $1,140 less on instruction.

About the only thing charters do well is limit the influence of teachers’ unions. And fatten their investors’ portfolios.

In part, it’s the tax code that makes charter schools so lucrative: Under the federal “New Markets Tax Credit” program that became law toward the end of the Clinton presidency, firms that invest in charters and other projects located in “underserved” areas can collect a generous tax credit — up to 39% — to offset their costs.

So basically they are hiding the costs of operation in tax credits (reducing tax revenue) to look like they are efficient.  I think it would be helpful to everyone if we counted tax expenditures as a form of spending.  So how is this plan to earn profits via education working out?  Just how good is this plan?

So attractive is the math, according to a 2010 article by Juan Gonzalez in the New York Daily News, “that a lender who uses it can almost double his money in seven years.”

or the salary of the CEO of one of the few publicly traded Charter School companies:

The story also revealed CEO Ronald Packard collected a salary in 2011 — $5 million — nearly double that of the previous year. And that his bonus is linked not to student performance, but to enrollment.

So the real issue here is that costs are not especially transparent and outcomes, on average are not especially wonderful:

Too bad the kids in charter schools don’t learn any better than those in plain-vanilla public schools. Stanford University crunched test data from 26 states. About a quarter of charters delivered better reading scores, but more than half produced no improvement, and 19% had worse results. In math, 29% of the charters delivered better math scores, while 40% showed no difference, and 31% fared worse.

Unimpressive, especially when you consider charter schools can pick and choose their students — weeding out autistic kids, for example, or those whose first language isn’t English. Charter schools in the District of Columbia are expelling students for discipline problems at 28 times the rate of the district’s traditional public schools — where those “problem kids” are destined to return.

So, even ignoring peer effects, these look like similar outcomes (the bias will be towards public schools doing worse because they cannot refuse students as easily).   

So I think two issues arise as matters of policy from these sorts of discussions.  One, it is hard to imagine why we need to disassemble a working system just to create lucrative investment opportunities.  Two, teacher job security and salary become much more salient as issues if they are compatible with decent student outcomes (one average, anecdotes will exist in all directions). 

I am not against innovation in education.  But I tend to be suspicious of drastic transformations of complex systems as they are hard to implement.  Nor is it reassuring that a business magazine is pointing this area out as a profit making opportunity.  Insofar as we have data, it isn't all that reassuring when we compare costs and benefits.   

h/t Mike the Mad Biologist and thanks to Mark Palko for comments

Weekend blogging -- the political cartoons of Dr. Seuss

As TPM pointed out, Ted Cruz made an odd choice when he invoked Theodor Geisel, a lifelong liberal who served as a political cartoonist for the left-wing PM.

Here at West Coast Stat Views, we're always hunting for an excuse to waste time looking at cartoons, so...

Which was also an reference to an earlier and very successful ad campaign

Hunger, homelessness and the George Foreman Grill

In the recent discussion of food stamps (see here, here, and here), one of the recurring points was that the price of food available in an area often played a relatively small role in the problem, particularly compared to the difficulties associated with not having access to flexible transportation or a decent kitchen.

Which brings up one of this blog's favorite villains, the dangers of having policy debated and decided by an economically and regionally homogeneous group. It's not just a case of not seeing things from other perspectives; it's a case of not seeing things from other perspectives and not knowing that you're doing it. When a well-meaning CEO recently tried to live on a SNAP budget for a week, he screwed up the easy part, but more importantly, he skipped the hard part, not because he was trying to cheat but because things like having a car were simply part of his world. 

I've been focusing on transportation, but having an adequate kitchen can be as or more important. I heard an interview with a man who had just gotten off the streets who explained it with the following example: if have a kitchen, you can get a dozen eggs for less than two dollars and have breakfast for a week; if you have to go to a restaurant, that same money will get you one egg sandwich. 

This 2004 NPR story illustrates the point beautifully and it also shows the resourcefulness people can show under difficult circumstances. 

So many immigrants, homeless people and others of limited means living in single-room occupancies (SROs) have no kitchens, no legal or official place to cook. To get a hot meal, or eat traditional foods from the countries they've left behind, they have to sneak a kind of kitchen into their places. Crock pots, hot plates, microwaves and toaster ovens hidden under the bed. And now, the latest and safest appliance, the appliance that comes in so many colors it looks like a modern piece of furniture: the George Foreman Grill. It is, quite literally, a hidden kitchen.
...
This story also led us to the streets. We called our colleague, Steve Edwards at WBEZ, to see if he could help us locate any hidden grills in Chicago. He contacted The Chicago Coalition for the Homeless, which in turn put us in touch with Jeffrey Newton. Jeffry has been homeless or in shelters most all his life, from boy's homes, to reformatories, to prison by age 17. Then he moved out on the streets, where every day he goes "trailblazing" — looking for food, shelter, work, the resources he needs to make it through the day.

Jeffry learned to cook from his grandmother. He feels an urge to cook, especially for other people — under the overpass on Chicago's Wacker Drive; on a George Foreman Grill plugged into a power pole; with a hot clothing iron to toast a grilled cheese sandwich.

We also called Glide Memorial Church in San Francisco's Tenderloin District. We knew they would know. They offer a stunning array of services to the poor, to those in recovery, to those needing assistance, both spiritual and physical.

Pat Sherman lived for quite some time in SROs with no kitchen, where cooking was forbidden. She now has a home and works in Glide's walk-in program. Sherman — whose recipe for "Hidden Beans & Rice" is linked to above — was quite ingenious when it came to cooking. Her Crock-Pot doubled as a pencil holder and a flower pot — nothing that would arouse suspicion. When nobody was around to check, she would slow-cook her beans while she went to school, then come home to a hot meal.

Reactions to DeLong's piece on Global Warming

I am sure that this section will be roundly ignored, but it was the most interesting to me: 

Even half a generation ago, economists interested in global warming like Thomas Schelling saw natural justice to this argument, and expected the North Atlantic to finance the carbon-neutral industrialization of the Global South--an environmental Marshall Plan for the 21st century. Global politics has not been kind to such dreams. I do not know of a way to represent a number as small as the probability that the next generation will see large-scale transfers from the North Atlantic to the Global South to fund its carbon-neutral industrialization.

But it may well be that continued inaction on dealing with global warming itself has mammoth antiegalitarian distributional consequences for the world. There are 2 billion peasants in the great river valleys of Asia from the Yellow to the Indus. Few of them have the human capital or the relationship chains needed to do well in the cities of Asia. For most of them, the economically valuable asset that they have the land that they farm--the land that requires for its economic value that there be enough melting snow off the Tibetan plateau but that the snow not melt too quickly. Global warming means either more or less snow on the Tibetan plateau. Why the governments of East Asia and South Asia are not now screaming about the consequences for their 2 billion peasants of global warming seems to me explicable only as the result of a strange kind of political myopia. To wait for large-scale transfers from the North Atlantic to begin carbon neutral industrialization in East Asia and South Asia seems to me likely to be viewed by historians a century from now as a classic dog-in-the-manger story.

I think that there are two levels that I really like this argument.  One, probably not surprising, is the public health argument.  The biosphere is under a lot of pressure -- pushing on it hard right now is likely to result in all sorts of adverse public health outcomes as things like water supplies become more constrained.  I think that the economic value argument (the melting snow makes the land economically valuable) is less salient than the potential for human suffering if there is a loss of food and clean water in this area.  DeLong doesn't address this directly, but I presume it is subsumed into the consequences of the economic changes. 

The second, though, is to think about the net present value of improved renewable energy sources.  Even with a modest discount rate, the development of improved solar, wind, or water energy production is huge because it extends the likely window of exploitation far into the future.  It is plausible that there might not be petroleum used as fuel in the future; the horizon over which the sun will stop providing energy likely exceeds the expected lifespan of the human race.  Heck, even Nuclear, with known disadvantages, has a much longer time horizon for viability.  This creates a real value to investment in these technologies as small improvement in efficiency could well pay large dividends. 

Of course, Mark would point out that existing technology is also potentially helpful as well. 

Netflix, the Emmys and the power of a happy narrative -- inevitable Motley Fool edition

This is getting sad.

As mentioned in a previous post, those journalists who cover either media or business or both have completely invested in the narrative of Netflix as visionary game changer. As a result they are compelled to put a positive spin on even the worst news such as this weekend's Emmy awards.

I had assumed it was inevitable that Motley Fool would join in. I had not realized, however, that they would actually join twice in the space of as many days, or that their efforts would be so, well, pathetic.

The first, "Why Netflix is still a buy," is merely embarrassing. Though it has a deadline of September 24, no mention is made of the Emmys. Instead we get a standard line about things looking great in Canada and about how people sure do watch a lot of television. All of which simply serves as a come on for one of Motley fool's promotional videos.

It's the second, though, that manages to exceed even Motley fool's standard of you've-got-to-be-kidding.In "Netflix Just Took Another Step Closer to Becoming HBO,"  Tim Beyers makes a full bore run at painting defeat as victory, favorably comparing House of Cards' Emmy performance to that of The Sopranos. Doing so requires grouping basically meaningless Creative Arts Emmys with the majors, underplaying the relatively low prestige of the directing Emmy and completely ignoring the fact that, based on reputation alone, David Fincher (Seven, Fight Club, Zodiac, and The Social Network) was always the favorite to win this category just as Martin Scorsese had been the favorite two years ago.

One of Motley Fool's favorite strategies is to pick a hot company like Netflix or Disney and relentlessly talk it up. Unlike the traditional pump-and-dump, the goal isn't to drive up that individual stock (it's hard to move a Disney); instead what's being pumped is the idea that you're losing money by not being in. This frame of mind makes readers receptive to buying MF's investment books and $199 newsletters even though, based on their columns, they have little to offer other than conventional wisdom and questionable analysis.

MF may not provide the worst investment advice you'll find...






But you can find better places to spend your money.

Why insurance is essential

This post gets to the heart of the reason why I consider the "insurance" piece of health insurance to be the less important part.  Being able to get favorable rates at the time of a medical emergency is far more important.  Consider: 

Lab testing is a vital part of modern healthcare, and can be a valuable tool in helping to diagnose many conditions and illnesses. But they can also be costly, especially if patients don’t pay attention to where their tests are being done. This can even be a problem for those with ‘comprehensive’ insurance, such as Mr. Marcovitz, when their insurer decides after the test is performed that they won’t cover a certain procedure. His story turned out OK, but most self-pay patients would likely have been stuck with a $2,000 bill for a test that they should only have paid $375.

It is fine to argue over whether statins should be covered by insurance, as a patient can actually get price quotes.  But it is less obvious that this is viable after being shot.   It is this emergency care piece of medical care that makes it impossible for a patient to comparison shop prices.  Heck, our ambulance system is completely set up for getting people to care fast and a seriously injured patient is simply not going to be able to bargain.  Imagine the "pay X now or go to hospital Y and pay Z, but on the way you will have irreversible heart damage due to a delay in treatment for your myocardial infarct".

Since the bargaining power in US medicine is entirely with insurers (private or government) this is actually a rather big deal. 

h/t The Incidental Economist

Getting a handle on the paradox of hunger in a country of abundant cheap food

Andrew Gelman has a good SNAP discussion going over at his blog. He also raises an interesting point about the implied statistical content of the previous posts on the subject. The following is a quick attempt (almost entirely dictated into my smartphone while walking to the bank) to make a few preliminary stabs at framing the problem:

We start with household diets. These are collections of individual diets. In some cases we can get economies of scale by combining these while in other cases it makes more sense for them to differ at certain points (for example, if one member is gluten intolerant or is on a low sodium diet). Just to standardize our terms, let's say that each days diet consist of four meals breakfast, lunch, dinner, and a snack. We measure the quality of each of these meals based on three metrics: nutrition, appeal, and how filling it is. Note, these metrics are not weighted symmetrically – a low score in any one of these areas is more bad than a high score is good. Therefore the first objective is to keep any of these metrics from falling below a satisfactory level. After that is achieved the secondary goal is to maximize these three.

Each meal consist of one or more dishes. Each dish consist of one or more ingredients. Everything interacts. One dish may go badly with another. A light dinner might be more acceptable after a heavy lunch.

These ingredients have to be purchased and prepared under various constraints. These include but are not limited to money, time and access.

The ingredients are bought at various stores. Each store is associated with certain time and transportation costs. For each ingredient, there are a wide range of factors that need to be considered before deciding a purchase. These include the quality of the dishes that can be prepared from these ingredients, the cost of the ingredients, how perishable these ingredients are, how easily they can be stored, and their versatility. To further complicate matters, these factors are sometimes dependent on what other ingredients are available, where they are being purchased and the quantities being bought. For example:

The quality, based on the previous listed metrics, of a dry breakfast cereal is dependent on the presence of milk;

The cost of a given item may be cheaper at one store but only if bought in large quantities;

If the constraint of only being able to shop at one store is added, shoppers may be forced to pay a premium price for being able to get all of the items needed for a given dish (99 cent store shoppers run into this problem frequently).

Now add to that the complexity that comes from the huge number of items that potentially may be included in our analysis and the wide range in personal situations.

Here are some examples of the latter:

An individual with a car in an urban area can probably select from a dozen or more stores and visit 2 to 4 of them in the space of an hour;

Outside of a few areas will served by public transportation, an individual in that same area without a car might only have a choice of three or four stores and might require a full 90 minutes to visit just one;

An ambulatory person in good health might be able to shop a 2 mile radius on foot;

The radius for a senior using a walker might be three blocks;

A working parent might find him or herself so time constrained that any shopping trip that takes more than an hour represents a severe sacrifice.

Finally add to that the need to put every meal on the table every day despite the fact that food consumption can be difficult to predict.

Just to be clear, we are talking about big effects here with substantial policy implications. Inappropriate or overly simplistic analyses can easily lead to disastrously wrong conclusions, but I'm not really the person to say what the appropriate approaches are. Maybe there's an epidemiologist in the audience with a suggestion or two...

The enormous difference that $4.45 a day can make

While on the subject of food stamps, you should check out the latest Paul Krugman column. He does a great job spelling out some of the touchstone points of the debate:

Still, is SNAP in general a good idea? Or is it, as Paul Ryan, the chairman of the House Budget Committee, puts it, an example of turning the safety net into “a hammock that lulls able-bodied people to lives of dependency and complacency.”

One answer is, some hammock: last year, average food stamp benefits were $4.45 a day. Also, about those “able-bodied people”: almost two-thirds of SNAP beneficiaries are children, the elderly or the disabled, and most of the rest are adults with children.

Beyond that, however, you might think that ensuring adequate nutrition for children, which is a large part of what SNAP does, actually makes it less, not more likely that those children will be poor and need public assistance when they grow up. And that’s what the evidence shows. The economists Hilary Hoynes and Diane Whitmore Schanzenbach have studied the impact of the food stamp program in the 1960s and 1970s, when it was gradually rolled out across the country. They found that children who received early assistance grew up, on average, to be healthier and more productive adults than those who didn’t — and they were also, it turns out, less likely to turn to the safety net for help.