Archive for April, 2012

Thought experiment: Suppose we were to institute a free market in medical finance—that is to say, permit consumers of medical care and producers of financial instruments to enter into whichever kinds of consensual transactions (pertaining to medical finance) they choose, without favoring any particular model(s) by means of public policy. What is there to fear in such a setup?

Concern #1: The poor would not be able to purchase a decent minimum of health care without giving up other essential spending (e.g., shelter). They do not deserve to be in this position—they consciously chose neither their genetic endowments, nor the childhood environments in which they were raised (nor the social circumstances they inherit, for that matter). It is unfair, therefore, to deny them standards of medical care that their more fortunate peers would be able to secure for themselves in the marketplace.

Reply: Indeed. The solution is to transfer wealth from those who have more of it to those who have less of it, up to a point. Such transfers discourage the creation of wealth. We must, therefore, delicately balance our desire for fairness with our desire for prosperity. I do believe, however, that doing so would leave us with ample room to improve the relative plight of the poor.

Concern #2: Cutting poor people checks is only part of the solution. What if, instead of purchasing necessary medical care, for example, a poor person blows her transfer payments on drugs?

Reply: Is she obviously engaging in self-destructive behavior? If she is, then there is a case for encouraging her to spend her money more constructively. A simple subsidy (e.g., a tax break) for buying essential medical care would probably do the trick. If she is obviously harming herself by not having particular financial products (for instance, catastrophic insurance, or a medical savings account), then specifically subsidizing her purchase of these is reasonable enough.

It is worth noting, however, that it is usually not obvious whether someone is engaging in self-destructive behavior. Our everyday decisions force us to make immeasurably complex calculations, which in turn draw upon extensive information about our preferences and the circumstances we inhabit, data concerning which is frequently inaccessible to outside observers.  This is neither to say that humans never engage in self-destructive behavior, nor that outsiders never improve upon the decisions of others. Instead, my claim is simply that it is not often the case that someone is obviously doing harm to themselves. As a consequence, the burden of proof is borne by those who want to encourage people to make different decisions—and it is a heavy burden indeed.

Concern #3: These proposals address the unfairness of some people being less wealthy than others, but they do not address the unfairness of some people being less healthy than others. Why should some have to pay more for medical care than others, simply because their health is in poorer condition (through no fault of their own, needless to say)?

Reply: It is not just sick people who have to pay more than their peers to remedy their God-given deficiencies. Ugly people, too, have to pay more than their peers to look better to others, to feel better about how they look, etc. Stupid people have to pay more than their peers to do better in school, or to do better on the job, etc. These observations do not serve to trivialize poor health. Instead, they underscore the uniqueness of economic inequality as a policy objective.

Usually, a very wealthy sick person is much better off than a very poor healthy person, because a poor person is likely to have many more problems to worry about besides her health, while having few resources to throw at such problems. A wealthy person, by contrast, is likely to have many fewer problems to worry about besides her health, while having a lot of resources to throw at the problem. The problem of poverty is not a problem of having inferior housing, or low-quality education, or inadequate nutrition—it is a problem of not having enough money. To a large (though far from complete) extent, the problem of ill health is a problem of not having enough money, too.

On a more practical note, just as transfers from rich to poor discourage wealth creation, transfers from healthy to sick encourage unhealthy lifestyle choices, which play a large role in shaping longer-term health outcomes (according to some experts, a much larger role than adequacy of medical care). Policies like ‘community rating’ effectively enact such transfers, driving up the cost of medical care in the long run. Consider this one more reason to focus discussions of fairness on economic inequality, rather than on health inequality.

Concern #4: What about spillover effects? Suppose people decide to forgo vaccination for a contagious disease, knowing that they may free ride on others’ vaccinations. Should we not encourage people to get vaccinated? Or consider the fact that our society simply is not going to let poor people with medical emergencies die in the streets. In light of guaranteed emergency care, should we not demand that everyone be able to pay up in the event of a medical emergency?

Reply: In principle, this is unobjectionable. In practice, it is a question of magnitudes. If the social cost of uncompensated emergency care, for example, is very high indeed, then mandating and subsidizing purchase of catastrophic health insurance is sensible enough. Similarly, if a disease is sufficiently dangerous and sufficiently contagious, subsidizing vaccinations is entirely appropriate. Where the social cost is low or negligible, the cure may prove to be worse than the disease, pardon the pun.

Another example relates to our earlier discussion of lifestyle choices. If the reason why uncompensated emergency care is so costly is that people are making unhealthy lifestyle choices (e.g., becoming obese), putting them at risk of various medical emergencies, then it may make more sense, depending on the science, to discourage obesogenic diets than to make insurance mandatory.

Concern #5: Even in the context of a fair distribution of wealth, a free market in health insurance would not work to the benefit of consumers. Since insurance companies would not know as much about a customer’s health as the customer herself, they would have to charge potentially very different customers roughly similar prices. This would cause healthier people to conclude insurance is a bad deal for them, dropping out of the pool, leaving it riskier on average. Responding to this, insurance companies would raise prices, causing still more (relatively) healthy people to drop out of the pool, causing prices to rise further, and so on and so forth. In equilibrium, the market would disappear, failing to serve the medical care financing needs of consumers.

Reply: This problem, known as ‘adverse selection’ in economics, is only a problem to the extent that insurance companies cannot bridge the informational divide. In reality, they work very hard to do this, under the heading of ‘medical underwriting’. Such screening procedures are hardly perfect, but then, consumers’ knowledge of their own health risks is hardly perfect, either. There is little evidence of adverse selection in existing health insurance markets, except in places where public policy actively discourages medical underwriting (e.g., through community rating and ‘guaranteed issue’ policies, which blunt insurer’s incentives to bridge the informational divide). Remember that the goal of such policies (greater equity in the distribution of medical care) is better pursued through explicit transfers, which neither cause adverse selection, nor discourage healthy lifestyle choices.

Concern #6: The case for free markets is premised upon competition. Competition between providers of medical finance ought to, in theory, drive down prices, while increasing quality. Why, then, do premiums keep rising in our medical insurance market? Why do these higher premiums largely support profits rather than better medical care? Is it not because the market for medical insurance is intrinsically non-competitive?

Reply: It is true that the market for medical insurance in the US is hardly competitive, but this is not intrinsic to the provision of medical insurance. Economies of scale in the insurance business do give larger firms a competitive edge over their smaller peers, but there are diminishing returns to scale, and there is little evidence that monopoly, or oligopoly, is the inevitable outcome of a free market in medical insurance. The US medical insurance market is mostly non-competitive due to regrettable public policies.

On the supply side, the US restricts competition between insurers across state lines. Given economies of scale, this encourages the formation of local monopolies. Additionally, a large number of regulations at the state and local levels raise the fixed costs of being in the insurance business, costs which it is easier for larger firms to bear—this, too, encourages insurance companies to scale up beyond what is socially optimal.

On the demand side, employer-provided health insurance is tax-deductible. Consequently, most workers get their insurance plans through their employer. For the majority of workers, the choice of the right job is much more important than the choice of the right health insurance plan. This bit of tax policy thus discourages workers from smart shopping in the insurance market. Employers, in turn, do not really care which insurance plans their employees have, for the cost of these plans is simply deducted from the wages they pay. There is, therefore, little pressure from the demand side for insurers to compete on price and quality.

Concern #7: What, then, should we do about people who, through no fault of their own, would be uninsured because of pre-existing conditions?

Reply: This question reflects a misunderstanding of the concept of insurance. Why do people buy medical insurance? They do so because their health is at risk (e.g., they may get hit by a bus), and they are willing to pay some amount for someone to take the associated medical risk (e.g., expenses for having their injuries treated) off of their hands. Why, then, do people sell medical insurance? They do so because even if the future health status of each of their customers is very unpredictable, the future health status of their entire pool of customers is reasonably predictable. This is a straightforward consequence of the Law of Large Numbers. As a result, insurers take on less medical risk than their customers compensate them for, yielding insurers profit. In short, the value of insurance is that, by pooling the risks of diverse customers, it reduces the aggregate risk borne by the pool as a whole.

What does this have to do with pre-existing conditions? Simple: if you have a pre-existing condition, there is no risk to be insured. For example, if you have cancer, there is no risk that you will demand expensive treatment—this is a certainty. “Insuring” certainties does not add value to anything. What people with pre-existing conditions need is not insurance, it is money. If someone already has plenty of money, public policy need not be concerned with her. If she does not, then the solution, once more, is to give her more money.

Requiring insurance companies to cover pre-existing conditions is to require them to get into a business besides insurance—namely, the business of pre-payment and/or redistribution. We should hardly expect insurance companies to be suited for this. What ever happened to specialization?

Conclusion: I could go on and on, but I think you get the point. There is little to fear in a free market in medical finance that a few, simple, well-designed subsidies cannot fix. Such subsidies warrant caution: I have been writing of the market for medical finance instead of the market for medical insurance, because this is not something we should pre-judge. Insurance was once a novel financial instrument. Innovation in medical finance may one day render it obsolete, which is something public policy should not get in the way of with outdated subsidies. Even today, we likely rely too much upon health insurance, when we should also be relying on medical savings (the tax-deductibility of employer-provided health insurance favors premium-heavy insurance plans over deductible-heavy plans, for example). Insofar as the many purported problems with free market health insurance are really problems, however, the right fix is delicate subsidies, not command-and-control regulation.

With the Supreme Court likely to strike down the PPACA’s individual mandate, comprehensive reform may soon be back on the agenda. Here’s to hoping that future proposals focus on deregulating the health insurance industry, ending the tax-deductibility of health insurance, and converting programs like Medicare and Medicaid into lump-sum subsidies for the poor. If, in such a liberalized, egalitarian environment, many people continue to do obvious damage to themselves by failing to purchase enough medical care, or by failing to purchase the right sorts of financial instruments pertaining to medical care, then we ought to discuss in more detail the merits of subsidizing this or that.

Of course, I have deliberately ignored the elephant in the room—the ballooning cost of medical care itself. For another day, I guess.


Think first about the following question: Why do we take seriously the claims to approximate truth of many natural scientific theories? We do so, in my view, mostly when such theories make predictions about observable phenomena that exhibit accuracy, precision, reliability, etc. These qualities do not exhaust the virtues of good natural scientific theories, but when a theory enjoys them to a great extent, its verisimilitude is hard to deny. The striking fact of a theory’s extraordinary predictive success cries out for explanation. The only non-miraculous explanation for this success, really, is that it is approximately true. A theory may have other features to recommend it, even if its predictions come up short, but the less compelling a theory’s predictive track record, the easier it is to explain its good qualities without invoking its approximate truth.

What, then, should be our view of social scientific models, the overwhelming majority of which fail to meet ordinary natural scientific standards of predictive success? If a model is internally consistent, then it correctly describes some possible world. One view of good social scientific models is that, even though they do not correctly describe our world (perhaps due to intrinsic complexities in our world), they correctly describe very similar (but much simpler) worlds. The natural sciences take this approach from time to time. Consider the ideal gas law—no one seriously believes that any gas in our world is ideal in the relevant sense, but most chemists believe that the world of ideal gases is very similar to our world. Social scientists may defend a model, knowing that it is not strictly correct in every particular, by insisting that the world of the model is so similar to reality that the model is still of great scientific value.

One problem with this defense is that the ideal gas law, like other successful natural scientific theories, makes very, very good predictions. Such successful predictions are very few and far between in the social sciences. If social scientists want to persuade others of the similarities between the worlds of their models and the real world, predictive success has to be the centerpiece of their argument.

A second, perhaps more serious problem with this defense is that social scientific models frequently incorporate ideas that we not only know to be false, strictly speaking, but also know to be not even approximately true. In rational choice models of human decision-making, for example, it is supposed that humans have complete, transitive preferences over their options. We know this is not true—indeed, we know this is not even approximately true.  Yet it continues to maintain a remarkable presence in many prominent social scientific models. Examples of this kind severely undermine the case outlined above for garden variety models in the social sciences.

If social scientific models do not qualify as successful scientific descriptions of our world—indeed, not even approximately true abstractions—then what ought we to make of them? The key to understanding social scientific models, in my view, is to recognize that many phenomena of interest need not occur only in our world, or only in very similar worlds. It is conceivable, for example, that recessions much like the ones that take place from time to time in our world take place from time to time in other, very different worlds. Some of these worlds may be much simpler than the real world, in that they obey only a handful of basic laws. Studying the properties and behavior of recessions in these worlds is more feasible than doing so in the real world, in which they co-occur with countless other complicating factors, even if these worlds have little else in common with the real world.

The challenge with investigating recessions in very different worlds is that features of recessions in those worlds may not carry over to the real world. These features may be intricately linked with the world in which they’re embedded, a world very different from our own. This is why robustness is important in such investigations. If we study a range of worlds that differ from each other along many of the same dimensions along which they each differ from the real world, then we may conclude that robust features of the phenomena being studied can conceivably carry over to our world, even if every world we study happens to be very much unlike our world.

As social scientists produce many such characterizations of phenomena of interest, each of which has properties and behaviors that do not necessarily depend upon the idiosyncrasies of the worlds in which they’re being studied, these characterizations may be compared with respect to their likeness to real world phenomena. The closer the match, the more compelling the characterization—though short of meeting ordinary scientific standards of predictive success, these characterizations need not enjoy the epistemic credentials of established physics, chemistry, etc.

On this understanding of social scientific models, it makes sense to separate two distinct kinds of debate. The first concerns the extent to which the account of phenomena embedded in the model corresponds to reality. The second concerns the extent to which the world of the model is a suitable environment in which to study the phenomena of interest. Note that this does not include debating the extent to which the world of the model corresponds to reality. The greater the extent to which this is the case, the better (of course), but the cost of this is typically greater analytical complexity. In light of this, it seems appropriate for some researchers to err on one side of this tradeoff, while the rest err on the other side.

This may not be the only way to do good social scientific research. This may not even be the best way to do social scientific research. It is, however, one way—one that is practiced much more often than other ways in some social sciences (e.g., economics), while playing a more minor role in others (e.g., cognitive psychology). In the end, I’m a pluralist. No one way of conducting social scientific inquiry has proven its worth to such a degree that other ways must be swept into the dustbin of history. The ‘model phenomena realistically, albeit in unrealistic settings’ method, if you will, has its limitations, to be sure, for which it ought to be criticized, if only to keep researchers’ eye on the prize, but it has something intellectually valuable to offer, too. Proponents of this approach do not consistently practice what they preach—this, too, ought to be extensively criticized—but when they do, they frequently yield novel perspectives on challenging problems, insights into which are always welcome, however they may be found.

The efficient market hypothesis (EMH) was once a widely believed theory in financial economics (see, for example, “Efficient Capital Markets” [Fama 1970]). The EMH states, informally, that financial market prices fully reflect publicly available information concerning the underlying value of the traded security. As expressed, the EMH gives rise to a joint-hypothesis problem: when directly determining whether a given financial market is pricing securities efficiently, one must suppose a particular model of underlying value. Should the EMH, coupled with such a model, fail the test, one is (logically) free to revise the pricing model without rejecting EMH.

Consequently, the EMH itself is usually tested in one of three ways: (1) ‘weak form’ tests explore whether one can consistently outperform the market as a whole by studying patterns in past price movements (i.e., whether technical analysis is a loser’s game in the long run); (2) ‘semi-strong form’ tests explore whether one can consistently outperform the market as a whole by studying publicly available information (i.e., whether fundamental analysis, too, is a loser’s game in the long run); (3) ‘strong form’ tests explore whether one can consistently outperform the market as a whole by having access to information that is only privately available (i.e., whether even insider trading is a loser’s game in the long run). Consistently outperforming the market is a challenge for the EMH, because the EMH implies that, going forward, price movements constitute a random walk, meaning that the limiting probability of consistently earning excess returns is precisely zero.

Why does the EMH imply that future price movements conform to a random walk? If the price of a security fully reflects publicly available information, then the only cause of future price movements is genuine news, which is by its very nature unpredictable. Hence, movements in future prices cannot be predicted, meaning that trading is purely a game of chance. It is certainly possible to win games of chance a large number of times (consider Warren Buffett’s career, for example), but the larger the number of games, the less likely consistent winning becomes.

Most proponents of EMH concede the observation of Grossman & Stiglitz [1980] that, if markets were efficient, it would not make sense for traders to sort through the news, thereby depriving markets of information needed to price securities efficiently. Thus, markets may well be efficient enough to deny traders much in the way of excess returns, but must be inefficient enough to continue to encourage informed trading.

The EMH near-consensus was supported by a large number of empirical studies showing that weak form, and many semi-strong form, tests of EMH conformed to the theory’s predictions (the track record of strong form tests is considerably more mixed). The consensus began to unravel when a number of criticisms from the behavioral finance school emerged, coupled with the increasing conviction of some econometricians that price movements may indeed be predictable. More recently, the EMH has faced a great deal of public criticism pertaining to its purported role in the financial crisis of 2007-2009. Many of these criticisms seem to me to be based upon some key confusions:

First, efficiency is a separate issue from stability. The fact that prices may run up, then suddenly fall off a cliff, does not necessarily condemn efficiency. Suppose, for example, that based upon the best information, housing seems to be a really good investment (perhaps because of a wave of immigration). Later, unexpectedly, compelling evidence to the contrary emerges (immigration seems to be slowing for whatever reason). Prices would rise sharply, then fall sharply, but there is nothing inefficient about this. It is just that, for a time, it was reasonable to believe housing to be a great investment, but this is no longer a reasonable belief. Instability is not necessarily evidence of inefficiency.

Second, efficiency does not imply perfect foresight. The claim of the EMH is that markets efficiently price securities based upon publicly available information, not that it prices securities based upon presently unknown considerations. The future is, to a very large extent, unpredictable. Expecting markets to get it right every time is folly.

Third, efficiency is a separate issue from rationality. Suppose a deeply irrational trader enters the market. His transactions cause a number of securities to become temporarily mispriced (with respect to efficiency). The consequence of this, however, is that rational traders now enjoy opportunities for arbitrage. Their efforts to profit off of this irrational trader will, in very short order, correct the mispricing. Thus, it is possible for many traders to be irrational, but for the market to still be efficient, so long as there are enough rational traders.

As for price trends, I will believe it when I see it. If you stare hard enough at any large data series, you will observe patterns therein. This does not mean, however, that you can reliably predict future price movements on the basis of past movements. If you can, then you can also profit off of those predictions. Where is the evidence of consistent excess returns derived from price trends? Show me the profit!

In my view, the EMH, like any good social scientific model, is a useful approximation for the purposes to which it is put, even if it is not precisely true. Assuming the EMH, we may infer from financial market prices what sorts of (rational) expectations traders have about future developments of interest. We may also explain why sticking with low-cost index funds makes more sense for casual investing purposes than turning one’s money over to expensive, actively managed funds. EMH may have this or that hole, but no alternative theory of financial market pricing gives us a useful interpretation of the relevant prices. Most importantly, no competitor theory can explain the most striking fact in finance: consistent excess returns are extremely, extremely hard to come by, in spite of some of the best and brightest working their very hardest using the most sophisticated tools to find them.

Productivity: a primer

Posted: April 6, 2012 by alephnaughty in Economics, Politics
Tags: , , ,

‘Productivity’ refers to the economic output produced by a unit of labor. Why does productivity matter? Suppose productivity is fixed. In order for the economy to produce more output, it must utilize more labor. More output means more income, which increases the quality of people’s leisure time. More labor, however, decreases the quantity of people’s leisure time. Hence, fixed productivity forces workers to choose between a higher quantity of lower quality leisure time, and a lower quantity of higher quality leisure time.

Greater productivity makes choosing between these two options unnecessary. Workers can increase the quantity, or the quality, of their leisure time without sacrificing the other. It’s a win-win…

…for the more productive workers. Where, though, does the added productivity come from? Productivity growth comes from capital accumulation. Capital, in turn, comes from saving–i.e., not consuming. Even though productivity growth is good for the workers whose productivity has grown, it requires sacrifice to bring it about. Some of that sacrifice may come from others (e.g., someone makes a bunch of money, invests it in equities, the purchased companies buy more powerful computers, making their workers more productive). Some of it may come from the worker himself (e.g, someone turns down opportunities to make money in order to go to school, enriching his human capital, making him more productive). But there is always sacrifice involved in bringing about greater productivity.

Productivity, too, therefore, is a matter of choice. Present-oriented people much prefer consumption today to consumption in the future, so choose to save less. This reduces the capital stock, slowing productivity growth, the consequence of which is a difficult tradeoff between the quantity and quality of future leisure. Future-oriented people have a more balanced perspective, so choose to save more. This increases the capital stock, accelerating productivity growth, the consequence of which is a (comparatively) easy tradeoff between the quantity and quality of future leisure.

Of course, it is more than mere choice that matters for productivity. Institutions and public policies, for one, matter immensely. But given a set of institutions and public policies, variations in productivity is largely reflected in variations in the discount rates people apply towards the future.

Market interest rates in the US have been historically low for quite some time now. Even long-term bonds, such as the 30-year US Treaury bond, are yielding extraordinarily low returns. What does this say about future productivity, and more importantly future living standards? To me, it says that people want to sacrifice now to a historic extent for the sake of a more prosperous future, which tells me people think the future is currently looking very dim indeed. When interest rates begin to rise to more historically normal levels, this will be because people have become more optimistic about the outlook for the US economy.

To be clear, I’m not calling for the Fed to raise interest rates. Interest rates are not extraordinarily low because the Fed wants them to be, but rather because the Fed has to follow the market’s lead in order to do its job of macroeconomic stabilization. The Fed is keeping rates low because people are pessimistic–not the other way around. The solution is to make people more optimistic about the future. In the near term, that’s mostly about stimulating demand/NGDP, but over longer horizons, the US needs to do something about what it appears to be headed for: a prolonged period of productivity stasis.