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Mostrando postagens com marcador American Economic Review. Mostrar todas as postagens
Mostrando postagens com marcador American Economic Review. Mostrar todas as postagens

quinta-feira, 20 de dezembro de 2012

F. Hayek: O Uso do Conhecimento na Sociedade (1945)

Uma transcrição longa, mas altamente relevante:

Hayek, Friedrich A. (1899-1992)
"The Use of Knowledge in Society"
American Economic Review. XXXV, No. 4, September 1945, pp. 519-30. American Economic Association
Available at: Library of Economics and Liberty, link: http://www.econlib.org/library/Essays/hykKnw1.html

The Use of Knowledge in Society
AER, 1945
I
H.1
What is the problem we wish to solve when we try to construct a rational economic order? On certain familiar assumptions the answer is simple enough. If we possess all the relevant information, if we can start out from a given system of preferences, and if we command complete knowledge of available means, the problem which remains is purely one of logic. That is, the answer to the question of what is the best use of the available means is implicit in our assumptions. The conditions which the solution of this optimum problem must satisfy have been fully worked out and can be stated best in mathematical form: put at their briefest, they are that the marginal rates of substitution between any two commodities or factors must be the same in all their different uses.
H.2
This, however, is emphatically not the economic problem which society faces. And the economic calculus which we have developed to solve this logical problem, though an important step toward the solution of the economic problem of society, does not yet provide an answer to it. The reason for this is that the "data" from which the economic calculus starts are never for the whole society "given" to a single mind which could work out the implications and can never be so given.
H.3
The peculiar character of the problem of a rational economic order is determined precisely by the fact that the knowledge of the circumstances of which we must make use never exists in concentrated or integrated form but solely as the dispersed bits of incomplete and frequently contradictory knowledge which all the separate individuals possess. The economic problem of society is thus not merely a problem of how to allocate "given" resources—if "given" is taken to mean given to a single mind which deliberately solves the problem set by these "data." It is rather a problem of how to secure the best use of resources known to any of the members of society, for ends whose relative importance only these individuals know. Or, to put it briefly, it is a problem of the utilization of knowledge which is not given to anyone in its totality.
H.4
This character of the fundamental problem has, I am afraid, been obscured rather than illuminated by many of the recent refinements of economic theory, particularly by many of the uses made of mathematics. Though the problem with which I want primarily to deal in this paper is the problem of a rational economic organization, I shall in its course be led again and again to point to its close connections with certain methodological questions. Many of the points I wish to make are indeed conclusions toward which diverse paths of reasoning have unexpectedly converged. But, as I now see these problems, this is no accident. It seems to me that many of the current disputes with regard to both economic theory and economic policy have their common origin in a misconception about the nature of the economic problem of society. This misconception in turn is due to an erroneous transfer to social phenomena of the habits of thought we have developed in dealing with the phenomena of nature.
II
H.5
In ordinary language we describe by the word "planning" the complex of interrelated decisions about the allocation of our available resources. All economic activity is in this sense planning; and in any society in which many people collaborate, this planning, whoever does it, will in some measure have to be based on knowledge which, in the first instance, is not given to the planner but to somebody else, which somehow will have to be conveyed to the planner. The various ways in which the knowledge on which people base their plans is communicated to them is the crucial problem for any theory explaining the economic process, and the problem of what is the best way of utilizing knowledge initially dispersed among all the people is at least one of the main problems of economic policy—or of designing an efficient economic system.
H.6
The answer to this question is closely connected with that other question which arises here, that of who is to do the planning. It is about this question that all the dispute about "economic planning" centers. This is not a dispute about whether planning is to be done or not. It is a dispute as to whether planning is to be done centrally, by one authority for the whole economic system, or is to be divided among many individuals. Planning in the specific sense in which the term is used in contemporary controversy necessarily means central planning—direction of the whole economic system according to one unified plan. Competition, on the other hand, means decentralized planning by many separate persons. The halfway house between the two, about which many people talk but which few like when they see it, is the delegation of planning to organized industries, or, in other words, monopoly.
H.7
Which of these systems is likely to be more efficient depends mainly on the question under which of them we can expect that fuller use will be made of the existing knowledge. And this, in turn, depends on whether we are more likely to succeed in putting at the disposal of a single central authority all the knowledge which ought to be used but which is initially dispersed among many different individuals, or in conveying to the individuals such additional knowledge as they need in order to enable them to fit their plans with those of others.
III
H.8
It will at once be evident that on this point the position will be different with respect to different kinds of knowledge; and the answer to our question will therefore largely turn on the relative importance of the different kinds of knowledge; those more likely to be at the disposal of particular individuals and those which we should with greater confidence expect to find in the possession of an authority made up of suitably chosen experts. If it is today so widely assumed that the latter will be in a better position, this is because one kind of knowledge, namely, scientific knowledge, occupies now so prominent a place in public imagination that we tend to forget that it is not the only kind that is relevant. It may be admitted that, as far as scientific knowledge is concerned, a body of suitably chosen experts may be in the best position to command all the best knowledge available—though this is of course merely shifting the difficulty to the problem of selecting the experts. What I wish to point out is that, even assuming that this problem can be readily solved, it is only a small part of the wider problem.
H.9
Today it is almost heresy to suggest that scientific knowledge is not the sum of all knowledge. But a little reflection will show that there is beyond question a body of very important but unorganized knowledge which cannot possibly be called scientific in the sense of knowledge of general rules: the knowledge of the particular circumstances of time and place. It is with respect to this that practically every individual has some advantage over all others because he possesses unique information of which beneficial use might be made, but of which use can be made only if the decisions depending on it are left to him or are made with his active coöperation. We need to remember only how much we have to learn in any occupation after we have completed our theoretical training, how big a part of our working life we spend learning particular jobs, and how valuable an asset in all walks of life is knowledge of people, of local conditions, and of special circumstances. To know of and put to use a machine not fully employed, or somebody's skill which could be better utilized, or to be aware of a surplus stock which can be drawn upon during an interruption of supplies, is socially quite as useful as the knowledge of better alternative techniques. And the shipper who earns his living from using otherwise empty or half-filled journeys of tramp-steamers, or the estate agent whose whole knowledge is almost exclusively one of temporary opportunities, or the arbitrageur who gains from local differences of commodity prices, are all performing eminently useful functions based on special knowledge of circumstances of the fleeting moment not known to others.
H.10
It is a curious fact that this sort of knowledge should today be generally regarded with a kind of contempt and that anyone who by such knowledge gains an advantage over somebody better equipped with theoretical or technical knowledge is thought to have acted almost disreputably. To gain an advantage from better knowledge of facilities of communication or transport is sometimes regarded as almost dishonest, although it is quite as important that society make use of the best opportunities in this respect as in using the latest scientific discoveries. This prejudice has in a considerable measure affected the attitude toward commerce in general compared with that toward production. Even economists who regard themselves as definitely immune to the crude materialist fallacies of the past constantly commit the same mistake where activities directed toward the acquisition of such practical knowledge are concerned—apparently because in their scheme of things all such knowledge is supposed to be "given." The common idea now seems to be that all such knowledge should as a matter of course be readily at the command of everybody, and the reproach of irrationality leveled against the existing economic order is frequently based on the fact that it is not so available. This view disregards the fact that the method by which such knowledge can be made as widely available as possible is precisely the problem to which we have to find an answer.
IV
H.11
If it is fashionable today to minimize the importance of the knowledge of the particular circumstances of time and place, this is closely connected with the smaller importance which is now attached to change as such. Indeed, there are few points on which the assumptions made (usually only implicitly) by the "planners" differ from those of their opponents as much as with regard to the significance and frequency of changes which will make substantial alterations of production plans necessary. Of course, if detailed economic plans could be laid down for fairly long periods in advance and then closely adhered to, so that no further economic decisions of importance would be required, the task of drawing up a comprehensive plan governing all economic activity would be much less formidable.
H.12
It is, perhaps, worth stressing that economic problems arise always and only in consequence of change. So long as things continue as before, or at least as they were expected to, there arise no new problems requiring a decision, no need to form a new plan. The belief that changes, or at least day-to-day adjustments, have become less important in modern times implies the contention that economic problems also have become less important. This belief in the decreasing importance of change is, for that reason, usually held by the same people who argue that the importance of economic considerations has been driven into the background by the growing importance of technological knowledge.
H.13
Is it true that, with the elaborate apparatus of modern production, economic decisions are required only at long intervals, as when a new factory is to be erected or a new process to be introduced? Is it true that, once a plant has been built, the rest is all more or less mechanical, determined by the character of the plant, and leaving little to be changed in adapting to the ever-changing circumstances of the moment?
H.14
The fairly widespread belief in the affirmative is not, as far as I can ascertain, borne out by the practical experience of the businessman. In a competitive industry at any rate—and such an industry alone can serve as a test—the task of keeping cost from rising requires constant struggle, absorbing a great part of the energy of the manager. How easy it is for an inefficient manager to dissipate the differentials on which profitability rests, and that it is possible, with the same technical facilities, to produce with a great variety of costs, are among the commonplaces of business experience which do not seem to be equally familiar in the study of the economist. The very strength of the desire, constantly voiced by producers and engineers, to be allowed to proceed untrammeled by considerations of money costs, is eloquent testimony to the extent to which these factors enter into their daily work.
H.15
One reason why economists are increasingly apt to forget about the constant small changes which make up the whole economic picture is probably their growing preoccupation with statistical aggregates, which show a very much greater stability than the movements of the detail. The comparative stability of the aggregates cannot, however, be accounted for—as the statisticians occasionally seem to be inclined to do—by the "law of large numbers" or the mutual compensation of random changes. The number of elements with which we have to deal is not large enough for such accidental forces to produce stability. The continuous flow of goods and services is maintained by constant deliberate adjustments, by new dispositions made every day in the light of circumstances not known the day before, by B stepping in at once when A fails to deliver. Even the large and highly mechanized plant keeps going largely because of an environment upon which it can draw for all sorts of unexpected needs; tiles for its roof, stationery for its forms, and all the thousand and one kinds of equipment in which it cannot be self-contained and which the plans for the operation of the plant require to be readily available in the market.
H.16
This is, perhaps, also the point where I should briefly mention the fact that the sort of knowledge with which I have been concerned is knowledge of the kind which by its nature cannot enter into statistics and therefore cannot be conveyed to any central authority in statistical form. The statistics which such a central authority would have to use would have to be arrived at precisely by abstracting from minor differences between the things, by lumping together, as resources of one kind, items which differ as regards location, quality, and other particulars, in a way which may be very significant for the specific decision. It follows from this that central planning based on statistical information by its nature cannot take direct account of these circumstances of time and place and that the central planner will have to find some way or other in which the decisions depending on them can be left to the "man on the spot."
V
H.17
If we can agree that the economic problem of society is mainly one of rapid adaptation to changes in the particular circumstances of time and place, it would seem to follow that the ultimate decisions must be left to the people who are familiar with these circumstances, who know directly of the relevant changes and of the resources immediately available to meet them. We cannot expect that this problem will be solved by first communicating all this knowledge to a central board which, after integrating all knowledge, issues its orders. We must solve it by some form of decentralization. But this answers only part of our problem. We need decentralization because only thus can we insure that the knowledge of the particular circumstances of time and place will be promptly used. But the "man on the spot" cannot decide solely on the basis of his limited but intimate knowledge of the facts of his immediate surroundings. There still remains the problem of communicating to him such further information as he needs to fit his decisions into the whole pattern of changes of the larger economic system.
H.18
How much knowledge does he need to do so successfully? Which of the events which happen beyond the horizon of his immediate knowledge are of relevance to his immediate decision, and how much of them need he know?
H.19
There is hardly anything that happens anywhere in the world that might not have an effect on the decision he ought to make. But he need not know of these events as such, nor of all their effects. It does not matter for him why at the particular moment more screws of one size than of another are wanted, why paper bags are more readily available than canvas bags, or why skilled labor, or particular machine tools, have for the moment become more difficult to obtain. All that is significant for him is how much more or less difficult to procure they have become compared with other things with which he is also concerned, or how much more or less urgently wanted are the alternative things he produces or uses. It is always a question of the relative importance of the particular things with which he is concerned, and the causes which alter their relative importance are of no interest to him beyond the effect on those concrete things of his own environment.
H.20
It is in this connection that what I have called the "economic calculus" proper helps us, at least by analogy, to see how this problem can be solved, and in fact is being solved, by the price system. Even the single controlling mind, in possession of all the data for some small, self-contained economic system, would not—every time some small adjustment in the allocation of resources had to be made—go explicitly through all the relations between ends and means which might possibly be affected. It is indeed the great contribution of the pure logic of choice that it has demonstrated conclusively that even such a single mind could solve this kind of problem only by constructing and constantly using rates of equivalence (or "values," or "marginal rates of substitution"), i.e., by attaching to each kind of scarce resource a numerical index which cannot be derived from any property possessed by that particular thing, but which reflects, or in which is condensed, its significance in view of the whole means-end structure. In any small change he will have to consider only these quantitative indices (or "values") in which all the relevant information is concentrated; and, by adjusting the quantities one by one, he can appropriately rearrange his dispositions without having to solve the whole puzzle ab initio or without needing at any stage to survey it at once in all its ramifications.
H.21
Fundamentally, in a system in which the knowledge of the relevant facts is dispersed among many people, prices can act to coördinate the separate actions of different people in the same way as subjective values help the individual to coördinate the parts of his plan. It is worth contemplating for a moment a very simple and commonplace instance of the action of the price system to see what precisely it accomplishes. Assume that somewhere in the world a new opportunity for the use of some raw material, say, tin, has arisen, or that one of the sources of supply of tin has been eliminated. It does not matter for our purpose—and it is very significant that it does not matter—which of these two causes has made tin more scarce. All that the users of tin need to know is that some of the tin they used to consume is now more profitably employed elsewhere and that, in consequence, they must economize tin. There is no need for the great majority of them even to know where the more urgent need has arisen, or in favor of what other needs they ought to husband the supply. If only some of them know directly of the new demand, and switch resources over to it, and if the people who are aware of the new gap thus created in turn fill it from still other sources, the effect will rapidly spread throughout the whole economic system and influence not only all the uses of tin but also those of its substitutes and the substitutes of these substitutes, the supply of all the things made of tin, and their substitutes, and so on; and all this without the great majority of those instrumental in bringing about these substitutions knowing anything at all about the original cause of these changes. The whole acts as one market, not because any of its members survey the whole field, but because their limited individual fields of vision sufficiently overlap so that through many intermediaries the relevant information is communicated to all. The mere fact that there is one price for any commodity—or rather that local prices are connected in a manner determined by the cost of transport, etc.—brings about the solution which (it is just conceptually possible) might have been arrived at by one single mind possessing all the information which is in fact dispersed among all the people involved in the process.
VI
H.22
We must look at the price system as such a mechanism for communicating information if we want to understand its real function—a function which, of course, it fulfils less perfectly as prices grow more rigid. (Even when quoted prices have become quite rigid, however, the forces which would operate through changes in price still operate to a considerable extent through changes in the other terms of the contract.) The most significant fact about this system is the economy of knowledge with which it operates, or how little the individual participants need to know in order to be able to take the right action. In abbreviated form, by a kind of symbol, only the most essential information is passed on and passed on only to those concerned. It is more than a metaphor to describe the price system as a kind of machinery for registering change, or a system of telecommunications which enables individual producers to watch merely the movement of a few pointers, as an engineer might watch the hands of a few dials, in order to adjust their activities to changes of which they may never know more than is reflected in the price movement.
H.23
Of course, these adjustments are probably never "perfect" in the sense in which the economist conceives of them in his equilibrium analysis. But I fear that our theoretical habits of approaching the problem with the assumption of more or less perfect knowledge on the part of almost everyone has made us somewhat blind to the true function of the price mechanism and led us to apply rather misleading standards in judging its efficiency. The marvel is that in a case like that of a scarcity of one raw material, without an order being issued, without more than perhaps a handful of people knowing the cause, tens of thousands of people whose identity could not be ascertained by months of investigation, are made to use the material or its products more sparingly; i.e., they move in the right direction. This is enough of a marvel even if, in a constantly changing world, not all will hit it off so perfectly that their profit rates will always be maintained at the same constant or "normal" level.
H.24
I have deliberately used the word "marvel" to shock the reader out of the complacency with which we often take the working of this mechanism for granted. I am convinced that if it were the result of deliberate human design, and if the people guided by the price changes understood that their decisions have significance far beyond their immediate aim, this mechanism would have been acclaimed as one of the greatest triumphs of the human mind. Its misfortune is the double one that it is not the product of human design and that the people guided by it usually do not know why they are made to do what they do. But those who clamor for "conscious direction"—and who cannot believe that anything which has evolved without design (and even without our understanding it) should solve problems which we should not be able to solve consciously—should remember this: The problem is precisely how to extend the span of our utilization of resources beyond the span of the control of any one mind; and therefore, how to dispense with the need of conscious control, and how to provide inducements which will make the individuals do the desirable things without anyone having to tell them what to do.
H.25
The problem which we meet here is by no means peculiar to economics but arises in connection with nearly all truly social phenomena, with language and with most of our cultural inheritance, and constitutes really the central theoretical problem of all social science. As Alfred Whitehead has said in another connection, "It is a profoundly erroneous truism, repeated by all copy-books and by eminent people when they are making speeches, that we should cultivate the habit of thinking what we are doing. The precise opposite is the case. Civilization advances by extending the number of important operations which we can perform without thinking about them." This is of profound significance in the social field. We make constant use of formulas, symbols, and rules whose meaning we do not understand and through the use of which we avail ourselves of the assistance of knowledge which individually we do not possess. We have developed these practices and institutions by building upon habits and institutions which have proved successful in their own sphere and which have in turn become the foundation of the civilization we have built up.
H.26
The price system is just one of those formations which man has learned to use (though he is still very far from having learned to make the best use of it) after he had stumbled upon it without understanding it. Through it not only a division of labor but also a coördinated utilization of resources based on an equally divided knowledge has become possible. The people who like to deride any suggestion that this may be so usually distort the argument by insinuating that it asserts that by some miracle just that sort of system has spontaneously grown up which is best suited to modern civilization. It is the other way round: man has been able to develop that division of labor on which our civilization is based because he happened to stumble upon a method which made it possible. Had he not done so, he might still have developed some other, altogether different, type of civilization, something like the "state" of the termite ants, or some other altogether unimaginable type. All that we can say is that nobody has yet succeeded in designing an alternative system in which certain features of the existing one can be preserved which are dear even to those who most violently assail it—such as particularly the extent to which the individual can choose his pursuits and consequently freely use his own knowledge and skill.
VII
H.27
It is in many ways fortunate that the dispute about the indispensability of the price system for any rational calculation in a complex society is now no longer conducted entirely between camps holding different political views. The thesis that without the price system we could not preserve a society based on such extensive division of labor as ours was greeted with a howl of derision when it was first advanced by von Mises twenty-five years ago. Today the difficulties which some still find in accepting it are no longer mainly political, and this makes for an atmosphere much more conducive to reasonable discussion. When we find Leon Trotsky arguing that "economic accounting is unthinkable without market relations"; when Professor Oscar Lange promises Professor von Mises a statue in the marble halls of the future Central Planning Board; and when Professor Abba P. Lerner rediscovers Adam Smith and emphasizes that the essential utility of the price system consists in inducing the individual, while seeking his own interest, to do what is in the general interest, the differences can indeed no longer be ascribed to political prejudice. The remaining dissent seems clearly to be due to purely intellectual, and more particularly methodological, differences.
H.28
A recent statement by Professor Joseph Schumpeter in his Capitalism, Socialism, and Democracy provides a clear illustration of one of the methodological differences which I have in mind. Its author is pre-eminent among those economists who approach economic phenomena in the light of a certain branch of positivism. To him these phenomena accordingly appear as objectively given quantities of commodities impinging directly upon each other, almost, it would seem, without any intervention of human minds. Only against this background can I account for the following (to me startling) pronouncement. Professor Schumpeter argues that the possibility of a rational calculation in the absence of markets for the factors of production follows for the theorist "from the elementary proposition that consumers in evaluating ('demanding') consumers' goods ipso facto also evaluate the means of production which enter into the production of these goods."*1
H.29
Taken literally, this statement is simply untrue. The consumers do nothing of the kind. What Professor Schumpeter's "ipso facto" presumably means is that the valuation of the factors of production is implied in, or follows necessarily from, the valuation of consumers' goods. But this, too, is not correct. Implication is a logical relationship which can be meaningfully asserted only of propositions simultaneously present to one and the same mind. It is evident, however, that the values of the factors of production do not depend solely on the valuation of the consumers' goods but also on the conditions of supply of the various factors of production. Only to a mind to which all these facts were simultaneously known would the answer necessarily follow from the facts given to it. The practical problem, however, arises precisely because these facts are never so given to a single mind, and because, in consequence, it is necessary that in the solution of the problem knowledge should be used that is dispersed among many people.
H.30
The problem is thus in no way solved if we can show that all the facts, if they were known to a single mind (as we hypothetically assume them to be given to the observing economist), would uniquely determine the solution; instead we must show how a solution is produced by the interactions of people each of whom possesses only partial knowledge. To assume all the knowledge to be given to a single mind in the same manner in which we assume it to be given to us as the explaining economists is to assume the problem away and to disregard everything that is important and significant in the real world.
H.31
That an economist of Professor Schumpeter's standing should thus have fallen into a trap which the ambiguity of the term "datum" sets to the unwary can hardly be explained as a simple error. It suggests rather that there is something fundamentally wrong with an approach which habitually disregards an essential part of the phenomena with which we have to deal: the unavoidable imperfection of man's knowledge and the consequent need for a process by which knowledge is constantly communicated and acquired. Any approach, such as that of much of mathematical economics with its simultaneous equations, which in effect starts from the assumption that people's knowledge corresponds with the objective facts of the situation, systematically leaves out what is our main task to explain. I am far from denying that in our system equilibrium analysis has a useful function to perform. But when it comes to the point where it misleads some of our leading thinkers into believing that the situation which it describes has direct relevance to the solution of practical problems, it is high time that we remember that it does not deal with the social process at all and that it is no more than a useful preliminary to the study of the main problem.

Notes for this chapter
1.
J. Schumpeter, Capitalism, Socialism, and Democracy (New York; Harper, 1942), p. 175. Professor Schumpeter is, I believe, also the original author of the myth that Pareto and Barone have "solved" the problem of socialist calculation. What they, and many others, did was merely to state the conditions which a rational allocation of resources would have to satisfy and to point out that these were essentially the same as the conditions of equilibrium of a competitive market. This is something altogether different from knowing how the allocation of resources satisfying these conditions can be found in practice. Pareto himself (from whom Barone has taken practically everything he has to say), far from claiming to have solved the practical problem, in fact explicitly denies that it can be solved without the help of the market. See his Manuel d'économie pure (2d ed., 1927), pp. 233-34. The relevant passage is quoted in an English translation at the beginning of my article on "Socialist Calculation: The Competitive 'Solution,' " in Economica, New Series, Vol. VIII, No. 26 (May, 1940), p. 125.

========

MLA Style
Hayek, Friedrich A., "The Use of Knowledge in Society." 1945. Library of Economics and Liberty. 20 December 2012. <http://www.econlib.org/library/Essays/hykKnw.html>.

APA Style
Hayek, Friedrich A. "The Use of Knowledge in Society." 1945. Library of Economics and Liberty. Retrieved December 20, 2012 from the World Wide Web: http://www.econlib.org/library/Essays/hykKnw.html

Turabian Style
Hayek, Friedrich A. "The Use of Knowledge in Society." American Economic Review. XXXV, No. 4. pp. 519-30. American Economic Association. 1945. Library of Economics and Liberty [Online] available from http://www.econlib.org/library/Essays/hykKnw.html; accessed 20 December 2012; Internet.

domingo, 13 de fevereiro de 2011

Os 20 melhores artigos em 100 anos da American Economic Review

Excelente ideia, excelente oportunidade para conhecer e ler alguns dos artigos mais famosos da história econômica, ou melhor, do pensamento econômico.
Paulo Roberto de Almeida

100 Years of American Economic Review: The Top 20 Articles
American Economic Review 101 (February 2011): 1–8
http://www.aeaweb.org/articles.php?doi=10.1257/aer.101.1.1
http://pubs.aeaweb.org/doi/pdfplus/10.1257/aer.101.1.1

The Top 20 Committee, consisting of Kenneth J. Arrow, B. Douglas Bernheim, Martin S. Feldstein, Daniel L. McFadden, James M. Poterba, and Robert M. Solow, was appointed by Robert Moffitt with the task of selecting the “Top 20” articles published in the American Economic Review during its first hundred years. We decided against trying to define formally the criteria for inclusion: they surely comprise sheer intellectual quality, influence on the ideas and practices of economists, and general significance or breadth; but it would be fruitless to try to specify the marginal rates of substitution among these and other qualities. We were looking for 20 admirable
and important articles.
As a starting point we used citation counts and numbers of searches in JSTOR. This is obviously important and relevant information, but not decisive on its own. Citation counts are biased in favor of subfields of economics with the largest populations. There is also a bias in favor of moderately recent articles, if only because the number of potential readers and writers has been increasing in time; very recent articles suffer from the fact that citations build up over time. In any case we were expected to use our judgment about quality and significance. So we used the citation and JSTOR data only to give us a large group of eligibles. We worried especially about overlooking articles in the very early days of the AER, some by great names in the history of economics. But we found, just to take one striking example, that although Irving Fisher published several articles in the journal, they were all minor or ephemeral pieces.
In the event, our early ballots showed an encouraging unanimity or near-unanimity, especially about the leading candidates. We very quickly converged on the Top 15 articles. There were occasional differences of opinion, only to be expected from a group with diverse interests, as we filled in the remaining three to five places. Here is our final list, arranged alphabetically, along with a brief reminder about each. There are few, if any, surprises.

100 Years of the American Economic Review:
The Top 20 Articles

By Kenneth J. Arrow, B. Douglas Bernheim, Martin S. Feldstein, Daniel L. McFadden, James M. Poterba, and Robert M. Solow*

Alchian, Armen A., and Harold Demsetz. 1972. “Production, Information Costs, and Economic Organization.” American Economic Review, 62(5): 777–95.
What is the special role of the firm in organizing production? The authors argue that it is the ability to measure inputs and their productivity and to allocate hired resources in production involving the cooperation of many inputs. It is this phenomenon that explains why all ooperation of factors does not take place through market-determined contracts. The firm is made to be the residual claimant because that approach creates the appropriate incentives for management. Many implications of this hypothesis are developed.

Arrow, Kenneth J. 1963. “Uncertainty and the Welfare Economics of Medical Care.” American Economic Review, 53(5): 941–73.
This paper provided a framework for thinking about the economics of the market for medical care using the language and tools of modern microeconomics. It argued that the aforementioned market is beset by market failures because consumers are exposed to risks that are not fully insurable (in large part due to problems of moral hazard), and because they lack the information and expertise required to assess risks and treatments. It hypothesized that various salient features of the institutions governing the provision of medical care are best understood as social adaptations aimed at redressing the resulting inefficiencies. It also noted that in some cases those institutional adaptations undermine competition and perversely contribute to inefficiency. Though written well prior to the emergence of the formal literature on asymmetric information, the paper anticipated many of the central issues that continue to occupy health economists today.

Cobb, Charles W., and Paul H. Douglas. 1928. “A Theory of Production.” American Economic Review, 18(1): 139–65.
The cliché surely applies here: this paper needs no introduction. The convenience and success of the constant-elasticity Cobb-Douglas function has spread its use from representing production possibilities, which was of course its original use, to representing utility functions and to much else throughout empirical and theoretical economics. Cobb and Douglas explored the elementary properties and implications of the functional form, and pointed to the approximate constancy of the relative shares of labor and capital in total income as the validating empirical fact.

Deaton, Angus S., and John Muellbauer. 1980. “An Almost Ideal Demand System.” American Economic Review, 70(3): 312–26.
A vast industry in applied econometrics analyzes the demand for specific products, and the impact on consumers of public and private policies that alter market equilibrium. This paper, building on the traditions of Cobb-Douglas, Stone, and Gorman, introduces a practical system of demand equations that are consistent with preference maximization and have sufficient flexibility to support full welfare analysis of policies that have an impact on consumers. The Deaton-Muellbauer system is now the standard for empirical analysis of consumer demand.

Diamond, Peter A. 1965. “National Debt in a Neoclassical Growth Model.” American Economic Review, 55(5): 1126–50.
Building on Paul Samuelson’s seminal work concerning consumption loans between individuals of different generations, this paper pioneered the analysis of overlapping generations (OLG) models with durable capital goods. It illuminated the properties of such models through two fundamental contributions. First, it demonstrated that the competitive equilibria of infinite horizon OLG models can be inefficient, even in the absence of conventional market failures. Second, it identified the mechanisms through which both external and internal debt can potentially reduce the capital stock. In clarifying the general equilibrium effects of displacing physical capital with government debt in individuals’ portfolios, it resolved a long-standing debate concerning the feasibility of using internal debt to shift the burden of paying for public expenditures to future generations.

Diamond, Peter A., and James A. Mirrlees. 1971. “Optimal Taxation and Public Production I: Production Efficiency.” American Economic Review, 61(1): 8–27.
Diamond, Peter A., and James A. Mirrlees. 1971. “Optimal Taxation and Public Production II: Tax Rules.” American Economic Review, 61(3): 261–78.
This paper, in two parts, is the foundation of the theory of optimal taxation and public production in the presence of second-best limitations on redistribution and private production. Diamond and Mirrlees show how the tax system can be tuned to minimize distortions and disincentives, and eliminate production inefficiencies. By subjecting tax systems to rigorous microeconomic analysis, this paper opened research on tax mechanism design and minimization of the burden of taxes.

Dixit, Avinash K., and Joseph E. Stiglitz. 1977. “Monopolistic Competition and Optimum Product Diversity.” American Economic Review, 67(3): 297–308.
Under monopolistic competition with differentiated goods and increasing returns to scale in each good, is there too much or too little product differentiation? This paper uses classical tools of microeconomics to answer this question, and in doing so, provides the foundation for an entire literature in which products are endogenous in number and attributes, and general equilibrium welfare analysis can be used to examine the consequences of tastes for variety.

Friedman, Milton. 1968. “The Role of Monetary Policy.” American Economic Review, 58(1): 1–17.
This presidential address is the origin of the “vertical long-run Phillips curve,” along with a contemporary paper by Edmund S. Phelps. It introduced the idea of a “natural” rate of unemployment as the only rate compatible with the sustained coincidence of actual and expected rates of inflation. This is the basis of the conclusion that the Phillips curve is vertical in the long run, allowing only a temporary trade-off between unemployment and inflation. From this followed possible implications for the conduct of macro-policy, especially monetary policy. An enormous amount of research and discussion followed.

Grossman, Sanford J., and Joseph E. Stiglitz. 1980. “On the Impossibility of Informationally Efficient Markets.” American Economic Review, 70(3): 393–408.
As pointed out by a number of scholars, in a world of dispersed information, the equilibrium price will itself in general be a source of information to participants, since it incorporates whatever information other participants have. Grossman and Stiglitz examine the implication for the case where information can be acquired at a cost. If there is an equilibrium, some will choose to get informed and others not; the two courses of action must be indifferent. (Very special assumptions are made about the risk aversion characteristics of the population and about its heterogeneity.) In particular, if some individuals can acquire perfect information at a finite cost, then no equilibrium exists, since, if information is acquired by some, it will be reflected in the price and so can be acquired costlessly by others, while if no one acquires
information, it will pay any individual to acquire it.

Harris, John R., and Michael P. Todaro. 1970. “Migration, Unemployment and Development: A Two-Sector Analysis.” American Economic Review, 60(1): 126–42.
This widely cited paper starts with the puzzle that in poor developing countries one observes individuals migrating from agricultural areas to urban areas, even though they would have positive marginal product in agriculture but face a substantial probability of unemployment in the urban area. The first step in the explanation is to note that there are politically determined minimum wages in the urban areas that prevent wages from adjusting to achieve full employment for all those who come to the urban areas. The equilibrium distribution of potential workers between the rural and urban areas equates the marginal product of labor in agriculture to the expected wage in the urban area, i.e., the product of the wage and the probability of employment.

Hayek, F. A. 1945. “The Use of Knowledge in Society.” American Economic Review, 35(4): 519–30.
The author addresses the fundamental question of the nature of the economic system and, in particular, its role in dealing with resource allocation when a fundamental knowledge base is distributed in small bits among a large population. The knowledge needed includes consumer valuations, production relations, and resource availabilities. In particular, general scientific principles, where expert opinion might be best, are only a small part of the knowledge base. The author argues for the importance of a price system in achieving coordination and efficiency in resource use without implying an impossible aggregation of information in a central place.

Jorgenson, Dale W. 1963. “Capital Theory and Investment Behavior.” American Economic Review, 53(2): 247–59.VOl. 101
This paper provided a theoretical framework for investment behavior based on a neoclassical theory of optimal capital accumulation. The paper introduced the user cost of capital as the key variable that combines the cost of finance (interest rates and equity yields) and tax rules (tax rates, depreciation schedules) and combined this user cost measure with the Cobb-Douglas production technology to obtain a desired stock of capital. Jorgenson then used the resulting implied optimal capital stock to derive an econometric equation for investment. Generalizations of the Jorgenson framework (e.g., to allow for more general production functions) made this the standard approach to the empirical study of the determinants of investment. The user cost of capital also became the key concept for the theoretical study of the effects of alternative tax rules.

Krueger, Anne O. 1974. “The Political Economy of the Rent-Seeking Society.” American Economic Review, 64(3): 291–303.
Many government policies, such as import licenses in developing nations, create rents for some market participants. While the presence of such rents and the distortions that they create have long been noted, this paper recognized the importance of “rent-seeking behavior” and explored its welfare implications. The paper’s central finding is that competitive rent-seeking increases the welfare costs of policies such as trade restrictions. In the context of import restrictions, this result strengthens the case for the use of tariffs rather than import quotas, since quotas create the possibility of rent-seeking behavior. By identifying the importance of rent-seeking activities and providing a framework for analyzing their welfare costs, this paper expanded the economic analysis of the government’s choice of policy instrument to achieve particular goals. It also helped to launch a voluminous literature on the role of corruption and governance in the process of economic development.

Krugman, Paul. 1980. “Scale Economies, Product Differentiation, and the Pattern of Trade.” American Economic Review, 70(5): 950–59.
The classical theory that foreign trade is determined by comparative advantage fails to explain some important observations, for example, that there is considerable trade in both directions within what is usually regarded as a single industry, and that countries tend to export goods for which the domestic demand is higher. Krugman investigates the determination of foreign trade under increasing returns; he assumes no difference in production conditions between countries.
Prices are determined by imperfect competition with costless product differentiation. Using Simple models, he formalizes foreign trade. When transport costs are introduced, he shows that each country will specialize, so no two will produce the same goods. The larger country will have terms of trade turned in its favor, and wages will be higher there. Some extensions of the model allow varieties within a single industry. It can then be shown that intra-industry trade can emerge and that countries will tend to export those commodities for which the domestic demand is highest.

Kuznets, Simon. 1955. “Economic Growth and Income Inequality.” American Economic Review, 45(1): 1–28.
Data from developing economies indicate that the earlier phases of economic development tend to be characterized by increasing income inequality, as those engaged in the small but growing modern sector of the economy pull away from those still left in agriculture and other Subsistence activities. The degree of inequality reaches a peak, however, and then diminishes with further development, as the modern sector comes to dominate the economy and perhaps more so if it creates room for redistributive activity. The resulting “Kuznets curve” has been the subject of much empirical research and discussion within development economics.

Lucas, Robert E., Jr. 1973. “Some International Evidence on Output-Inflation Tradeoffs.” American Economic Review, 63(3): 326–34.
This article introduces a tight but stylized model in which market participants must make decisions without knowing whether local changes in price signal changes in relative price or merely reflect changes in the general price level; they do, however, know the statistical properties of both processes. From this basis emerges a naturalrate model in which the ratio of real-output change to price-level change in response to exogenous shifts in aggregate expenditure depends on the relative variance of those processes. Time-series cross-section data for a number of countries provide some weak evidence consistent with the basic conclusion. The underlying assumption has gone out of favor, but the modeling technique has been very Influential.

Modigliani, Franco, and Merton H. Miller. 1958. “The Cost of Capital, Corporation Finance and the Theory of Investment.” American Economic Review, 48(3): 261–97.
A central question in corporate finance is how a firm’s financial choices, such as its use of debt rather than equity financing, affect its cost of capital and consequently its investment Behavior. This paper developed a new framework for addressing this question by asking how different debt-equity choices would affect the total market value of all of the cash flows that the firm provided to its investors, both bond-holders and stock-holders. The paper’s central result is that, in a setting with complete capital markets and in the absence of tax-induced distortions, a firm’s total market value is invariant to its borrowing behavior. This powerful result can be demonstrated constructively, by developing a straightforward set of borrowing or
lending transactions that an equity investor can undertake to offset the consequences of changes in corporate borrowing. The analytical approach in this paper is one of the key foundations for the modern field of financial economics.

Mundell, Robert A. 1961. “A Theory of Optimum Currency Areas.” American Economic Review, 51(4): 657–65.
This paper explains that selecting the optimal geographic area for a single currency involves balancing two considerations. Macroeconomic stability is enhanced if the currency area has a high degree of internal factor mobility relative to the cross-border factor mobility. Taken by itself, this could lead to an excessively large number of currency areas, in the sense that There would be substantial transaction costs and valuation costs involved in making cross-area purchases. The optimal size of a currency area involves balancing these two considerations. Mundell discussed the potential application of this to the European countries some 30 years before the euro was introduced.

Ross, Stephen A. 1973. “The Economic Theory of Agency: The Principal’s Problem.” American Economic Review, 63(2): 134–39.
This paper was the first to describe and analyze the canonical principal-agent problem with moral hazard, which has since become a cornerstone of microeconomic theory. It solved for the optimal compensation scheme using the first-order approach, and compared the solution to the first-best arrangement, noting that the two generally diverge due to the principal’s need to motivate the agent. It characterized the class of utility functions for which the principal’s solution is first-best optimal regardless of the payoff structure, as well as the class of payoff structures for which the solution is first-best optimal regardless of the utility functions. In only a handful of terse pages, it anticipated many of the central issues with which the subsequent literature was concerned.

Shiller, Robert J. 1981. “Do Stock Prices Move Too Much to Be Justified by Subsequent Changes in Dividends?” American Economic Review, 71(3): 421–36.
Standard models of asset market equilibrium imply that the value of a share of corporate stock equals the present discounted value of that stock’s expected future payouts. This paper applied an ingenious test of this present value relationship, which compared the variance of annual stock price movements with the variance in corporate dividend payouts, to the US equity market for the period 1870–1979. The results suggested that historical stock price volatility was much greater than the volatility of dividend payouts would appear to warrant. This empirical finding
stimulated a wide range of follow-on research exploring various aspects of the efficient markets hypothesis, testing for time-varying discount rates in capital markets, and investigating the econometric properties of stock market returns and corporate payouts.

REFERENCES
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Arrow, Kenneth J. 1963. “Uncertainty and the Welfare Economics of Medical Care.” American Economic Review, 53(5): 941–73.
Cobb, Charles W., and Paul H. Douglas. 1928. “A Theory of Production.” American Economic Review,
18(1): 139–65.
Deaton, Angus S., and John Muellbauer. 1980. “An Almost Ideal Demand System.” American Economic Review, 70(3): 312–26.
Diamond, Peter A. 1965. “National Debt in a Neoclassical Growth Model.” American Economic
Review, 55(5): 1126–50.
Diamond, Peter A., and James A. Mirrlees. 1971. “Optimal Taxation and Public Production I: Production Efficiency.” American Economic Review, 61(1): 8–27.
Diamond, Peter A., and James A. Mirrlees. 1971. “Optimal Taxation and Public Production II: Tax
Rules.” American Economic Review, 61(3): 261–78.
Dixit, Avinash K., and Joseph E. Stiglitz. 1977. “Monopolistic Competition and Optimum Product
Diversity.” American Economic Review, 67(3): 297–308.
Friedman, Milton. 1968. “The Role of Monetary Policy.” American Economic Review, 58(1): 1–17.
Grossman, Sanford J., and Joseph E. Stiglitz. 1980. “On the Impossibility of Informationally Efficient Markets.” American Economic Review, 70(3): 393–408.
Harris, John R., and Michael P. Todaro. 1970. “Migration, Unemployment and Development: A Two Sector Analysis.” American Economic Review, 60(1): 126–42.
Hayek, F. A. 1945. “The Use of Knowledge in Society.” American Economic Review, 35(4): 519–30.
Jorgenson, Dale W. 1963. “Capital Theory and Investment Behavior.” American Economic Review,
53(2): 247–59.
Krueger, Anne O. 1974. “The Political Economy of the Rent-Seeking Society.” American Economic
Review, 64(3): 291–303.
Krugman, Paul. 1980. “Scale Economies, Product Differentiation, and the Pattern of Trade.” American Economic Review, 70(5): 950–59.
Kuznets, Simon. 1955. “Economic Growth and Income Inequality.” American Economic Review,
45(1): 1–28.
Lucas, Robert E., Jr. 1973. “Some International Evidence on Output-Inflation Tradeoffs.” American Economic Review, 63(3): 326–34.
Modigliani, Franco, and Merton H. Miller. 1958. “The Cost of Capital, Corporation Finance and the Theory of Investment.” American Economic Review, 48(3): 261–97.
Mundell, Robert A. 1961. “A Theory of Optimum Currency Areas.” American Economic Review,
51(4): 657–65.
Ross, Stephen A. 1973. “The Economic Theory of Agency: The Principal’s Problem.” American Economic Review, 63(2): 134–39.
Shiller, Robert J. 1981. “Do Stock Prices Move Too Much to Be Justified by Subsequent Changes in
Dividends?” American Economic Review, 71(3): 421–36.

* Arrow: Stanford Institute for Economic Policy Research (SIEPR), Stanford, CA 94305; Bernheim: Stanford University Department of Economics, Economics Building, 247 Stanford, California 94305; Feldstein: National Bureau of Economic Research, 1050 Massachusetts Avenue, Cambridge, MA 02138; McFadden: University of California, Berkeley, Department of Economics, 508-1 Evans Hall, Berkeley, CA 94720; Poterba: MIT Department of Economics, 50 Memorial Drive, Building E52, Room 350, Cambridge MA 02142; Solow: MIT Department of Economics, 50 Memorial Drive, Building E52, Cambridge MA 02142. We thank Jeffrey Hovis and Andrew McLetchie of JSTOR for their assistance. The 20 articles featured in this paper are available in the online version at
http://www.aeaweb.org/articles.php?doi=10.1257/aer.101.1.1.2