Sunday, February 27, 2011

This round just might go to Eminem

Edward L. Glaeser has been tough on Detroit and the auto industry. Here's how he opened a column last week:
During the Super Bowl, Chrysler and Eminem gave us a chest-thumping, soul-lifting vision of Detroit as a city of character, competence and style. But the Census tells us that per-capita incomes in Detroit are barely half the national average and that one-third of the city lives in poverty.

Michigan was the only state that lost people from 2000 to 2010, and the state’s unemployment rate remains near 12 percent. Is it possible that Detroit will turn the corner despite decades of decline?

It's safe to assume that the answer Glaeser had in mind for his rhetorical question didn't rely too much on the Big Three. Back in June, 2009, here's what he had to say about the bailouts:
Since the collapse of Lehman Brothers, the public sector has spent billions saving the banks. While these decisions are certainly debatable, they are understandable. The US financial industry misbehaved badly,... but it is still a sector with a future. ... After all, every other sector in the economy depends on banks for their financing.

But what about cars? ... Does anyone, other than GM's management, believe that this company can come back? The current treatment, cash infusion and a reduction in corporate liabilities, provides a solution for a company that is broke, not for one that is broken.
Given that analysis, it might be interesting to get his take on this item from the New York Times:
General Motors, which nearly collapsed from the weight of its debts two years ago before reorganizing in a government-sponsored bankruptcy, said Thursday that it earned $4.7 billion in 2010, the most in more than a decade.
It was the first profitable year since 2004 for G.M., which became publicly traded in November, ending a streak of losses totaling about $90 billion.
In addition, G.M. said 45,000 union workers would receive profit-sharing checks averaging $4,300, the most in the company’s history. ...
Globally, G.M.’s sales rose 12.2 percent in 2010, to 8.39 million, coming within about 30,000 vehicles of retaking the title of world’s largest automaker from Toyota. For the first time, it sold more cars and trucks in China, where its sales rose 28.8 percent from 2009, than in the United States, where sales were up 6.3 percent.

Or to see what he had to say about Jonathan Cohn's reaction to the news:

Seriously, though, this is another important milestone for GM. Profits for the final quarter were actually lower than initial expectations. But the company attributed that, in part, to heavy investment in the development of new products, which is a sign of company health. “Their recovery has been fueled by significant cost-cutting, arrival of new products that consumers were seeking along with better management of incentives and supply,” Jesse Toprak, vice president of industry trends and insight at TrueCar.com, told the Times. “The sky is the limit for G.M. after becoming profitable at this low of a sales pace.”

Of course, the usual caveats apply: The two companies could still stumble and Chrysler, in particular, still needs to prove they can cars as good as their television commercials. And it's not as if workers in the auto industry didn't take a huge hit anyway: Many did lose their jobs and new employees are making a lot less money than old ones do.

Still, it looks increasingly like the rescue of the auto industry was an overall success, saving hundreds of thousands (if not millions) of jobs and bolstering the country's manufacturing base for years (if not decades) to come. Maybe it's time to start giving President Obama some credit for it--and recognizing that, when properly managed, the federal government can do a lot of good.

Saturday, February 26, 2011

Weekend Gaming -- Piet Hein's TacTix

A Grook by Piet Hein:

ARS BREVIS

There is
one art,
no more,
no less:
to do
all things
with art-
lessness.


Piet Hein was, among many other things, an inventor of remarkably clever games. After Hex,* his most famous is probably his two-dimensional variant on nim, TacTix.



As with most of Hein's recreations (even those dealing with sophisticated mathematical concepts), the rules of TacTix are wonderfully simple. The players take turns picking up pieces from the board (shown above) until the losing player is forced to pick up the last piece. The players can pick up as many pieces at a time as they choose with the only constraint being that the pieces have to be in the same row or column and have to be contiguous.

Here's what what a game might look like after a couple of moves (taken from this sample game):

TacTix doesn't quite meet Othello's "a minute to learn a lifetime to master" standard, it yields fairly easily to analysis (or to practice if you're paying attention), but while this keeps it out of competition with chess and Go and less well-known games like agon, Hein's invention still has a lot to offer:

The rules are almost as simple as TicTacToe, making it an ideal game for very young players;

Like TicTacToe, TacTix can easily be played as a pencil-and-paper game. Just mark off a grid then cross out squares instead of removing pieces;

Unlike more complicated games, the underlying concepts of TacTix are easy to grasp and to teach (Martin Gardner had a good summary in one of his Scientific American columns though I'm not sure where it's collected);

TacTix also makes an excellent programming exercise;

Finally, there's no rule that says you have to follow the rules. Try adding a few of your own. Play around with the board configuration or try flipping a coin to determine whether you can pick up an odd or even number of pieces. Get creative. It's what Hein would have wanted.






* Also independently invented by John Nash a few years later.

Friday, February 25, 2011

Interesting paper on peer effects

I'm not sure this is the ideal methodology to approach this problem (I'd like to see this combined with something that captures the actual interactions in the classroom), but, based on what I've seen, this is a definite improvement.

From VoxEU (via Thoma)

Our recent research uncovers peer effects in education as distinct from the contextual and other correlated influences. Our econometric strategy uses the topological structure of social networks as well as network fixed effects to identify each of these effects separately.

Our analysis is made possible by the use of a unique database on friendship networks from the National Longitudinal Survey of Adolescent Health (AddHealth). The AddHealth database has been designed to study the impact of the social environment (i.e. friends, family, neighbourhood and school) on adolescents' behaviour in the US by collecting data on students in grades 7-12 from a nationally representative sample of roughly 130 private and public schools in years 1994-95 (wave I). A subset of adolescents selected from the rosters of the sampled schools, was then interviewed again in 1995-96 (wave II), in 2001-2 (wave III), and again in 2007-2008 (wave IV). For our purposes, the most interesting aspect of the AddHealth data is the friendship information, which is based upon actual friend nominations. It is collected at wave I, i.e. when individuals were at school. Indeed, pupils were asked to identify their best friends from a school roster (up to five males and five females). As a result, we can reconstruct the whole geometric structure of the friendship networks.

In Calvó-Armengol et al. (2008), we exploit such information to test a peer-effect model which relates analytically equilibrium behaviour to network location. This analysis shows that the structure of friendships ties is an important, and so far unnoticed, determinant of a pupil performance at school. In Patacchini et al. (2011), we follow this line of research by exploiting the other AddHealth waves in order to investigate whether such effect is carried over time. Indeed, the longitudinal structure of the survey provides information on both respondents and friends during the adulthood. In particular, the questionnaire of wave IV contains detailed information on the highest education qualification achieved.

We analyse the impact of the friends' educational attainment on an individual's educational attainment where they are identified as friends during school and in to adulthood. We find that peer effects in education are not only strong but also persistent over time. We find that the most relevant peers are the friends people make in grade 10-12, from when they are around 15 years old. This suggests that individuals are more likely to work towards and apply to college if this choice is popular among their peers, especially in the last years at school. This could represent the effect of contagion and collective socialisation and mean that any education policy targeting specific individuals will have multiplier effects.

Thursday, February 24, 2011

So many problems for such a little state

As if this weren't enough.

From TPM:
According to The Providence Journal, "[s]chool and city leaders said they were forced to issue the mass dismissal notices because of a state law that says teachers must be notified about possible layoffs or terminations by March 1." In a statement, Mayor Angel Taveras said that because the deadline for informing teachers about employment changes came before the budget for next year could be determined, the move was necessary.

"Providence faces significant challenges in getting its financial house in order," Taveras said in the statement. "Spending reductions are inevitable. It is also inevitable that some portion of cuts will come from the school budget. This is why we faced the difficult decision of sending letters to all teachers: we do not yet know what actions will be required and believe it was only fair to let all teachers know about the severity of the situation."

Taveras told the Journal that there would be fewer schools open, and fewer teachers teaching, in Providence next year -- he just couldn't yet say how many.

I hope to have a post up later today on the economics and logistics of hiring and firing of teachers. One of the relevant sub-topics here is the highly compressed hiring season. It is difficult and terribly disruptive (particularly for the students) to make staffing changes during the school year. Unlike most fields where employer and/or employee has the option of deciding that a position isn't a good fit, a teaching assignment represents a decision that all parties will have to live with for the next year.

The result? Take a year's worth of staffing for a labor-intensive industry, up the stakes, then squeeze the whole thing into eight or ten weeks. That's the reality of managing the education workforce. Any viable reform proposal based on changing the way we hire and fire teachers has got to either work under those constraints or fix the system.

Evidence

John D Cook has a very nice post up about evidence in science:

Though it is not proof, absence of evidence is unusually strong evidence due to subtle statistical result. Compare the following two scenarios.

Scenario 1: You’ve sequenced the DNA of a large number prostate tumors and found that not one had a particular genetic mutation. How confident can you be that prostate tumors never have this mutation?

Scenario 2: You’ve found that 40% of prostate tumors in your sample have a particular mutation. How confident can you be that 40% of all prostate tumors have this mutation?

It turns out you can have more confidence in the first scenario than the second. If you’ve tested N subjects and not found the mutation, the length of your confidence interval around zero is proportional to N. But if you’ve tested N subjects and found the mutation in 40% of subjects, the length of your confidence interval around 0.40 is proportional to √N. So, for example, if N = 10,000 then the former interval has length on the order of 1/10,000 while the latter interval has length on the order of 1/100. This is known as the rule of three. You can find both a frequentist and a Bayesian justification of the rule here.

Absence of evidence is unusually strong evidence that something is at least rare, though it’s not proof. Sometimes you catch a coelacanth.


Now it is true that this approach can be carried too far. The comments section has a really good discussion of the limitations of this type of reasoning (it doesn't handle sudden change points well, for example).

But it is worth noting that a failure to find evidence (despite one's best attempts) does tell you something about the distribution. So, for example, the failure to find a strong benefit for users of Vitamin C on mortality, despite a number of large randomized trials, makes the idea that this drug is actually helpful somewhat less likely. It is true we could look in just one more population and find an important effect. Or that it is only useful in certain physiological states (like the process of getting a cold) which are hard to capture in a population based study.

But failing to find evidence of the association isn't bad evidence, in and of itself that the association is unlikely.

P.S. For those who can't read the journal article, the association between Vitamin C and mortality is Relative Risk 0.97 (95% Confidence Interval:0.88-1.06), N=70 456 participants (this includes all of the trials).

Wednesday, February 23, 2011

You'll notice they said nothing about the op-eds being fit to print

An unnamed friend of Jonathan Chait had some fun re-editing a recent Tom Friedman column:
A wake-up call’s mother is unfolding. At the other end is a bell, which is telling us we have built a house at the foot of a volcano. The volcano is spewing lava, which says move your house. The road will be long and rocky, but it will trigger a shift before it kicks. We can capture some of it. IF the Middle East was a collection of gas stations, Saudi Arabia would be a station. Iran, Kuwait , Bahrain, Egypt, Libya, Iraq, and the United Arab Emirates would all be stations. Guys, here’s the deal. Don’t hassle the Jews. You are insulated from history. History is back. Fasten your seat belts. Don’t expect a joy ride because the lid is blowing off. The west turned a blind eye, but the report was prophetic, with key evidence. Societies are frozen in time. No one should have any illusions. Root for the return to history, but not in the middle.*
Which brought to mind this memorably representative passage from Maureen Dowd:
Mr. Obama called W. on Friday to give him a heads-up about the repudiation on Iraq. Robert Gibbs said the call was not at all contentious. But in the Lehrer interview, the president compared America to a big tanker that needed to "start moving in a better trajectory so that five years, 10 years down the road you can say, you know what, because of good decisions now our kids are safer, more secure, more prosperous, more unified than they were before." This analogy turns W. into the Exxon Valdez.
Dowd's attempts at analogies often go something like that, a collection of elements vaguely related to the topic at hand but without analogous relationships (like when she called Joe Biden a human lie detector because he compulsively told the truth). You could make an analogy where Bush was Captain Hazelwood or the U.S. under Bush was the Valdez, but what you have here isn't an analogy; it's just word association.

The sad part is that Dowd's plum position is based on her writing and analytic abilities. Unlike Friedman, and, for that matter, Brooks and Krugman (both of whom can actually write), Dowd brings no special expertise to her columns. All she offers are her prose and her insights, both of which are terrible. And yet the halo effect of the New York Times was strong enough to pull in a Pulitzer.

And the really sad part is that both Friedman and Dowd are better than John Tierney.

* To be fair, Friedman's main points are quite a bit better than his prose.

"Just around the corner" for about a century




The rate of technological progress is an incredibly complex subject and is open to interpretation depending on how you define your terms and weight your metrics. I see a huge surge starting around the 1870s and running more or less uninterrupted* through the 1960s followed by a perhaps inevitable leveling off to a more sustainable rate in the past few decades but I've heard well-reasoned arguments that paint a completely different picture.

Having acknowledged this diversity of opinion, there's still a wonderful irony to using a video phones to counter the argument that technology isn't delivering what was promised because we were promised video phones for an awfully long time. As early as 1891, Alexander Graham Bell was thinking seriously about the subject:
"Should it be found... [that the image sensor] is illuminated, then an apparatus might be constructed in which each piece of selenium is a mere speck, like the head of a small pin, the smaller the better. The darkened selenium should be placed in a cup-like receiver which can fit over the eye… Then, when the first selenium speck is presented to an illuminated object, it may be possible that the eye in the darkened receiver, should perceive, not merely light, but an image of the object… "
By 1930, AT&T was testing prototypes. By 1936, the German postal service had a public video phone service available. Research into wireless systems was going on at the same time.

And through all this, for about a hundred years, there was a constant stream of stories in newspapers and magazines like Popular Science announcing that it wouldn't be long before every home had a video phone. Young boys and girls who grew up reading these stories died of old age reading the same headlines. Given this history, it's difficult to be that impressed by the rate of innovation.

I would argue that for the past few decades, most areas of technology have advanced at about the rate we expected with more areas under-performing than exceeding expectations. There are any number good arguments to the contrary, but none of them use the video phone as an example.

p.s. I don't think great-granddad would be all that dazzled by texting either.



* I'm not sure about the Thirties. Does anyone have any thoughts on the effects of the Great Depression on technology?

"Don't worry, honey, the other children won't judge you on your looks."

Joseph recently brought up the subject of separated-twin studies. Let's take things to the next level with a thought experiment using clones. We'll have to go full-bore mad scientist mode here and assume we have exclusive access not only to an unlimited supply of clones but to undetectable plastic surgery techniques that can be performed without the subject's knowledge.

From early childhood, we assign different treatment combinations to different groups of our genetically identical subjects. We adjust features to match those that tend to elicit strong responses in terms of attractiveness, intelligence, likeability, and other traits. We modify height and body type, again making sure to cover the extremes. We even determine vocal characteristics.

After about thirty years of this, we assess the subjects using a variety of personal, professional, and academic metrics, the same sort of metrics often used in twin studies.

Now we come to the big question, are you willing bet a sizeable amount of money that none of these treatments are significant? If the answer is no, you shouldn't put a lot of faith in twin studies that measure these same factors because these studies never control for appearance.

How we look does not determine who we are but it does have a big impact on the life that we lead. It makes people more or less likely to want to hang out with us (particularly if those people see us as potential mates). Through the halo effect it affects people's opinion of us (including opinions in the form of grades and professional evaluations). Perhaps most importantly, it changes the way we see ourselves.

Separated twin studies have often been held up as a gold standard. Pyrite might be a more apt description. The data are invariably confounded in numerous ways that are difficult to correct for. In addition to the factors mentioned above, twins (barring surrogacy) share a prenatal background, the same relative age compared to their classmates and the same absolute age. You could easily find yourself comparing a pair of twins who suffered from mild FAS, were the youngest students in their classes, and were born in 1960 against a pair of twins who had excellent prenatal care, were the oldest in their classes and who were born in 1950.

Twins can be incredibly useful as test subjects, but the popular notion that these separated twin studies provide clean, unambiguous findings is simply wrong. Every one of them has serious problems with confounded data and these problems hold even for perfect studies with twins separated at birth, randomly assigned to adoptive parents and kept isolated from each other (conditions that aren't met that often). Personally, I have trouble overlooking all these concerns and putting a lot of weight into these findings, but, of course, I didn't inherit a trusting nature.

Tuesday, February 22, 2011

Goodbye little buddy



This is a cat named Turtle, who will be sorely missed by his adoptive parents. He had a unique ability to express himself and has left a Turtle sized hole the lives of all who knew him. Rest in peace, little buddy.

"Especially when it’s done wrong"

Felix Salmon has another intriguing (and, more to the point, important) post on saving and investing based on this (also intriguing and important) paper by Wade Pfau on saving and investing. I won't try to summarize but I have to quote this one paragraph.
Investing can be exciting, especially when it’s done wrong. You follow the markets rising and falling, you obsess about your retirement-fund balance, you rotate out of this and into that, you read books and magazines and blogs to try to learn more about what to do. You might even, in a moment of weakness, find yourself watching CNBC. Budgeting, by contrast, is like going on a diet: it’s a drag, and it’s hard to get any pleasure or excitement out of it. But the latter is much more likely to get you well-set in retirement than the former.

There is no market solution to the blankonomics problem

And obviously God has not listened to our prayers to end the plague:

Spousanomics: Using Economics to Master Love, Marriage, and Dirty Dishes

From Yahoo's Shine:
Splitting the dishes, laundry, vacuuming, and other household chores may seem fair, but an unbending line right down the middle can lead to more friction, not less, because no one is good and fast at all things. But when couples adopt the economic principle of “comparative advantage,” which says it’s not efficient to take on every task you’re good at, only the ones you are relatively better at, couples can gain time for the things they really want to do, the authors write.

“In economics, having the comparative advantage in something means you produce it at a lower cost and really quickly,”* Paula Szuchman said in an interview with Yahoo! Shine. So if one of you is better at laundry, then do it. And if the other can do the dishes and clean up the kitchen faster every night, while the better cook cooks, go for it.

The authors, both accomplished journalists (Szuchman: Wall Street Journal and Anderson: New York Times, where she spent years covering Wall Street and delivered award-winning coverage of Merrill Lynch) decided the time was right for an economics-approach how-to for a successful union for a few reasons. One was a pretty tough first year of marriage for Szuchman, who was surprised it was harder than she thought to merge two lives and that “something as banal as housework could get in the way” of all the fun she heard people were having being married. Another was the prevalence of economic terms suddenly in the national lexicon at the time of the financial meltdown. All at once, terms like “moral hazard” and “loss aversion” were all over the news to help explain a seemingly unexplainable economic freefall. “There seemed to be some useful parallels,” Szuchman said.
If you can get beyond the incredibly annoying title (and I can think of no reason you should), the fundamental analogy is still fatally flawed. Economic approaches tend to be reductionist; they work best on problems with clearly defined objectives and components that can easily and accurately be assigned scalar metrics (problems distinctly unlike those involving relationships).

If the purpose of a marriage were to optimize the completion of chores, the authors might be on to something other than a band wagon here, but, of course, that's not why people enter into the institution. This is not to say that things like chores can't have a major impact on a relationship or even that the advice the authors give about dividing up chores based on competence is necessarily bad, but that even if the authors are right here, they are still using a terrible model.

A flawed model may occasionally, simply by accident, lead to an accurate prediction, but so can guessing and in one important way guessing is far superior. The model brings with it a sense of rigor and reliability, of intellectual seriousness. With a guess you know what you're getting.

* Maybe an economist out there can help me out. This sounds like absolute advantage -- "I can do A better than you." I thought comparative advantage was something like this "I can do A better than B and better than you can do A (or at least more profitably). Your B is as good or better than your A (though possibly not as good as my B). I should focus on A (because of the opportunity costs of B) and you should focus on B."

Anyone care to clear this up?

Monday, February 21, 2011

Environment is complex

Via Tyler Cowen:

A case in point is provided by the recent study of regular tobacco use among SATSA's twins (24). Heritability was estimated as 60% for men, only 20% for women. Separate analyses were then performed for three distinct age cohorts. For men, the heritability estimates were nearly identical for each cohort. But for women, heritability increased from zero for those born between 1910 and 1924, to 21% for those in the 1925-39 birth cohort, to 64% for the 1940-58 cohort. The authors suggested that the most plausible explanation for this finding was that "a reduction in the social restrictions on smoking in women in Sweden as the 20th century progressed permitted genetic factors increasing the risk for regular tobacco use to express themselves." If purportedly genetic factors can be so readily suppressed by social restrictions, one must ask the question, "For what conceivable purpose is the phenotypic variance being allocated?" This question is not addressed seriously by MISTRA or SATSA. The numbers, and the associated modeling, appear to be ends in themselves.


The idea that culture, itself, is an environmental exposure does shed some serious doubt on twin studies as the gold standard to separate genetic and environmental influences on phenotypes. Tyler Cowen says it well here:

"Culture" and "genes" are two major factors determining individual outcomes, toss in parenting, and if you wish call parenting and culture two parts of "environment." It is obvious that culture matters a great deal, and this comes from knowledge which existed prior to rigorous behavioral genetic studies.

I say "soda" and people in Nebraska say "pop." Singapore vs. southern China. German musical tastes in 1780 vs. today. Rural Africa vs. urban Africa. Most concretely, if I meet someone I want to know what country he came from and grew up in; in fact that is the first thing I wish to know. "The culture word" may be overused and abused, but still the power of culture is evident.


I think that we should think carefully about how quick we are to ascribe behaviors to genetics (once we account for within culture variability) without considering between culture variability. Even worse, it is not clear that the modern world has a sufficient degree of cultural variation (given our connectivity in the modern world) to even measure this parameter properly.

Mark also has another insight as to a limitation of twin studies that I hope he posts at some point.

A nice comment on investment strategies

James Joyner:

Aside from diversifying one’s portfolio over both time and scope of investments, there’s no great option. As I recently told an investment counselor who was encouraging me to move investments from one fund to a one that “would have a higher rate of growth,” if she really had the ability to accurately predict which stocks would go up, she wouldn’t need to be advising clients for a living. Anyone who claims to know what the market is going to do over the long term is an idiot or a liar.


I think that this comment is right on. I always get worried with investment professionals (who gets paid based on a percentage of your portfolio and not based on how it performs) giving advice on very specific investment options. Diversification and dollar cost averaging are the only elements that really seem to be under my control. Otherwise, as Mark says, focusing on savings is your best option to control your ability to retire.

The unreliable magic of compound interest

Felix Salmon has been doing remarkably good work recently but this column stood out as particularly relevant:

My point is that the range of remotely sensible investment strategies for a working person is actually pretty narrow. You can’t just wave a magic asset-allocation wand and change your annualized return over a period of 35 years by 300 basis points. Frankly, you’d be doing well if you could improve it by 30 basis points. The market will return whatever the market will return and you will do a little bit worse than that, most likely.

So the way to have a comfortable retirement is not to think that by making a clever choice when it comes to stock-picking or investment strategy that you can somehow make up for the money you’re spending rather than saving. Instead, it’s to diligently save as much as you can, from as early an age as possible and simply invest it in a non-idiotic manner. The more you save, especially in your 20s and 30s, the more you’ll end up with in retirement.

Wall Street would love us to believe that the magic of compound interest gives us a free lunch; that a small amount of savings, if compounded at a high enough rate, can set us up for life. That might be true mathematically, but saving doesn’t work that way in the real world. Interest rates are low, now, and wages are growing sluggishly.

The three big drivers of big retirement accounts — sharply rising salaries, sharply rising house prices and a sharply rising stock market — are all looking very uncertain these days. So let’s not perpetuate this pipe dream that if only we can get an 8% return on our funds, everything will be fine. Because chances are we won’t. Absent that 8% return, the only way of getting to where we want to be is to simply spend less and save more.

There are two factors here: how much you save and how effectively you manage that savings. An entire industry has grown up around the second, usually based on appallingly optimistic estimates, often bordering on the fraudulent.

These financial gurus have done their best to popularize the idea that a good investment strategy was more important than how much money you put away and they've tried their hardest to avoid the unpalatable truth that there is only one aspect of our financial futures we have any real control over. Most of us can't really choose how much we'll make and we certainly can't control the performance of the market but we can decide how much of our disposable income to spend.

Spend less, save more, and ignore everything you hear on CNBC.

Another note on Herman Mankiewicz, Peter Bogdanovich, and the definition of 'hack'

Following up on an earlier topic, I had known that Herman Mankiewicz had worked on the Wizard of Oz, but I had left it out of this post because I assumed his contribution was insignificant. Then I came across this:
In February, 1938, he was assigned as the first of ten screenwriters to work on The Wizard of Oz. Three days after he started writing he handed in a seventeen-page treatment of what was later known as "the Kansas sequence". While Baum devoted less than a thousand words in his book to Kansas, Mankiewicz almost balanced the attention on Kansas to the section about Oz. He felt it was necessary to have the audience relate to Dorothy in a real world before transporting her to a magic one. By the end of the week he had finished writing fifty-six pages of the script and included instructions to film the scenes in Kansas in black and white. His goal, according to film historian Aljean Harmetz, was to "to capture in pictures what Baum had captured in words--the grey lifelessness of Kansas contrasted with the visual richness of Oz." He was not credited for his work on the film, however.
Aljean Harmetz certainly knows what she's talking about and, if she's quoted accurately, this would require an awfully broad definition of 'hack.'