Daron Acemoglu

From the dynamic defense lawyer who masterminded Claus von Bulow's successful appeal and subsequent acquittal comes the inside story of the decade's most celebrated society scandal. Alan M. Dershowitz unfolds a legal detective story of remarkable excitement. Von Bulow's trials were courtroom extravaganzas, teeming with sex and drugs, mistresses and maids, socialites and sleaze -- and many unanswered questions. Did von Bulow inject his wife, Sunny, with an overdose of insulin to gain her fortune and marry his mistress? Or was he the victim of a bereaved family member or friend who couldn't believe that Sunny had destroyed herself? Dershowitz first presents the evidence that was used to convict von Bulow, then shows how he and the defense team amassed arguments, testimony and new physical evidence that demolished the prosecution's case. He takes the reader behind the locked gates of Clarendon Court and inside the infamous black bag to make clear for the first time how two juries could come to such different verdicts. - Jacket.

We study the efficiency of oligopoly equilibria in a model where firms compete over capacities and prices. The motivating example is a communication network where service providers invest in capacities and then compete in prices. Our model economy corresponds to a two-stage game. First, firms (service providers) independently choose their capacity levels. Second, after the capacity levels are observed, they set prices. Given the capacities and prices, users (consumers) allocate their demands across the firms. We first establish the existence of pure strategy subgame perfect equilibria (oligopoly equilibria) and characterize the set of equilibria. These equilibria feature pure strategies along the equilibrium path, but off-the-equilibrium path they are supported by mixed strategies. We then investigate the efficiency properties of these equilibria, where efficiency is defined as the ratio of surplus in equilibrium relative to the first best. We show that efficiency in the worst oligopoly equilibria of this game can be arbitrarily low. However, if the best oligopoly equilibrium is selected (among multiple equilibria), the worst-case efficiency loss has a tight bound, approximately equal to 5/6 with 2 firms. (cont.) This bound monotonically decreases towards zero when the number of firms increases. We also suggest a simple way of implementing the best oligopoly equilibrium. With two firms, this involves the lower-cost firm acting as a Stackelberg leader and choosing its capacity first. We show that in this Stackelberg game form, there exists a unique equilibrium corresponding to the best oligopoly equilibrium. We also show that an alternative game form where capacities and prices are chosen simultaneously always fails to have a pure strategy equilibrium. These results suggest that the timing of capacity and price choices in oligopolistic environments is important both for the existence of equilibrium and for the extent of efficiency losses in equilibrium. Keywords: capacity, competition, efficiency loss, industry structure, investment oligopoly. JEL Classifications: C72, L13.

Is inequality harmful for economic growth? Is the underdevelopment of Latin America related to its unequal distribution of wealth? A recently emerging consensus claims not only that economic inequality has detrimental effects on economic growth in general, but also that differences in economic inequality across the American continent during the 19th century are responsible for the radically different economic performances of the north and south of the continent. In this paper we investigate this hypothesis using unique 19th century micro data on land ownership and political office holding in the state of Cundinamarca, Colombia. Our results shed considerable doubt on this consensus. Even though Cundinamarca is indeed more unequal than the Northern United States at the time, within Cundinamarca municipalities that were more unequal in the 19th century (as measured by the land gini) are more developed today. Instead, we argue that political rather than economic inequality might be more important in understanding long-run development paths and document that municipalities with greater political inequality, as measured by political concentration, are less developed today. We also show that during this critical period the politically powerful were able to amass greater wealth, which is consistent with one of the channels through which political inequality might affect economic allocations. Overall our findings shed doubt on the conventional wisdom and suggest that research on long-run comparative development should investigate the implications of political inequality as well as those of economic inequality.

We analyze an economy where managers engage both in the adoption of technologies from the world frontier and in innovation activities. The selection of high-skill managers is more important for innovation activities. As the economy approaches the technology frontier, selection becomes more important. As a result, countries at early stages of development pursue an investment-based strategy, with long-term relationships, high average size and age of firms, large average investments, but little selection. Closer to the world technology frontier, there is a switch to an innovation-based strategy with short-term relationships, younger firms, less investment and better selection of managers. We show that relatively backward economies may switch out of the investment-based strategy too soon, so certain economic institutions and policies, such as limits on product market competition or investment subsidies, that encourage the investment-based strategy may be beneficial. However, societies that cannot switch out of the investment based strategy fail to converge to the world technology frontier. Non-convergence traps are more likely when policies and institutions are endogenized, enabling beneficiaries of existing policies to bribe politicians to maintain these policies. Keywords: appropriate institutions, convergence, economic growth, innovation, imitation, political economy of growth, selection, technical change, traps. JEL Classifications: O31, O33, O38, O40, L16.

This paper studies a simple model of experimentation and innovation. Our analysis suggests that patents may improve the allocation of resources by encouraging rapid experimentation and efficient ex post transfer of knowledge across firms. Each firm receives a private signal on the success probability of one of many potential research projects and decides when and which project to implement. A successful innovation can be copied by other firms. Symmetric equilibria (where actions do not depend on the identity of the firm) always involve delayed and staggered experimentation, whereas the optimal allocation never involves delays and may involve simultaneous rather than staggered experimentation. The social cost of insufficient experimentation can be arbitrarily large. Appropriately-designed patents can implement the socially optimal allocation (in all equilibria). In contrast to patents, subsidies to experimentation, research, or innovation cannot typically achieve this objective. We also show that when signal quality differs across firms, the equilibrium may involve a non-monotonicity, whereby players with stronger signals may experiment after those with weaker signals. We show that in this more general environment patents again encourage experimentation and reduce delays. Keywords: delay, experimentation, innovation, patents, research. JEL Classifications: O31, D83, D92 Working Paper Series.

Many developing countries have suffered under the personal rule of "kleptocrats", who implement highly inefficient economic policies, expropriate the wealth of their citizens, and use the proceeds for their own glorification or consumption. We argue that the success of kleptocrats rests, in part, on their ability to use a "divide-and-rule" strategy, made possible by weakness of the institutions in these societies. Members of society need to cooperate in order to depose a kleptocrat, yet such cooperation may be defused by imposing punitive rates of taxation on any citizen who proposes such a move, and redistributing the benefits to those who need to agree to it. Thus the collective action problem can be intensified by threats which remain off the equilibrium path. In equilibrium, all are exploited and no one challenges the kleptocrat. Kleptocratic policies are more likely when foreign aid and rents from natural resources provide rulers with substantial resources to buy off opponents; when opposition groups are shortsighted; when the average productivity in the economy is low; and when there is greater inequality between producer groups (because more productive groups are more difficult to buy off). Keywords: dictatorship, divide-and-rule, economic development, institutions, kleptocracy, personal rule, political economy. JEL Classifications: O12, H00.

This paper documents that the Rise of (Western) Europe between 1500 and 1850 is largely accounted for by the growth of European nations with access to the Atlantic, and especially by those nations that engaged in colonialism and long distance oceanic trade. Moreover, Atlantic ports grew much faster than other West European cities, including Mediterranean ports. Atlantic trade and colonialism affected Europe both directly, and indirectly by inducing institutional changes. In particular, the growth of New World, African, and Asian trade after 1500 strengthened new segments of the commercial bourgeoisie, and enabled these groups to demand, obtain, and sustain changes in institutions to protect their property rights. Furthermore, the most significant institutional changes and consequently the most substantial economic gains occurred in nations where existing institutions placed some checks on the monarchy and particularly limited its control of overseas trading activities, thus enabling new merchants in these countries to benefit from Atlantic trade. Therefore, the Rise of Europe was largely the result of capitalist development driven by the interaction of late medieval institutions and the economic opportunities offered by "Atlantic trade." Keywords: Capitalism, Economic Growth, Institutions, Political Economy, Social Conflict, Trade. JEL Classification: O10, F10, P10, N13.

We propose two related equilibrium refinements for voting and agenda-setting games. Sequentially Weakly Undominated Equilibrium (SWUE) and Markov Trembling Hand Perfect Equilibrium (MTHPE), and show how these equilibrium concepts eliminate non-intuitive equilibria that arise naturally in dynamic voting games and games in which random or deterministic sequences of agenda-setters make offers to several players. We establish existence of these equilibria in finite and infinite (for MTHPE) games, provide a characterization of the structure of equilibria, and clarify the relationship between the two concepts. Finally, we show how these concepts can be applied in a dynamic model of endogenous club formation. Keywords: voting, agenda-setting games, Markov trembling-hand perfect equilibrium. JEL Classifications: D72, C73.

Despite the major advances in information technology that have shaped the recent wave of globalization, openness to trade is still a political choice, and trade policy can change with shifts in domestic political equilibria. This paper suggests that a particular threat and a limiting factor to globalization and its future developments may be militarist sentiments that appear to be on the rise among many nations around the globe today. We proxy militarism by spending on the military and the size of the military, and document that over the past 20 years, countries experiencing greater increases in militarism according to these measures have had lower growth in trade. Focusing on bilateral trade flows, we also show that controlling flexibly for country trends, a pair of countries jointly experiencing greater increases in militarism has lower growth in bilateral trade. Keywords: globalization, trade, military spending, militarism, nationalism. JEL Classifications: F01, F10, F52.

We study the formation of a ruling coalition in political environments. Each individual is endowed with a level of political power. The ruling coalition consists of a subset of the individuals in the society and decides the distribution of resources. A ruling coalition needs to contain enough powerful members to win against any alternative coalition that may challenge it, and it needs to be self-enforcing, in the sense that none of its subcoalitions should be able to secede and become the new ruling coalition. We first present an axiomatic approach that captures these notions and determines a (generically) unique ruling coalition. We then construct a simple dynamic game that encompasses these ideas and prove that the sequentially weakly dominant equilibria (and the Markovian trembling hand perfect equilibria) of this game coincide with the set of ruling coalitions of the axiomatic approach. We also show the equivalence of these notions to the core of a related non-transferable utility cooperative game. In all cases, the nature of the ruling coalition is determined by the power constraint, which requires that the ruling coalition be powerful enough, and by the enforcement constraint, which imposes that no subcoalition of the ruling coalition that commands a majority is self-enforcing. (cont.) The key insight that emerges from this characterization is that the coalition is made self-enforcing precisely by the failure of its winning subcoalitions to be self-enforcing. This is most simply illustrated by the following simple finding: with simple majority rule, while three-person (or larger) coalitions can be self-enforcing, two-person coalitions are generically not self-enforcing. Therefore, the reasoning in this paper suggests that three-person juntas or councils should be more common than two-person ones. In addition, we provide conditions under which the grand coalition will be the ruling coalition and conditions under which the most powerful individuals will not be included in the ruling coalition. We also use this framework to discuss endogenous party formation. Keywords: coalition formation, collective choice, cooperative game theory, political economy, self-enforcing coalitions, stability. JEL Classifications: D71, D74, C71.

This paper revisits the induced innovation literature of the 1960s to which Phelps was a major contributor (Drandakis and Phelps, 1965). This literature was the first systematic study of the determinants of technical change and also the first investigation of the relationship between factor prices and technical change. I present a modern reformulation of this literature based on the tools developed by the endogenous growth literature. This reformulation confirms many of the insights of the induced innovations literature, but reveals a new force, which I refer to as the market size effect: there will be more technical change directed at more abundant factors. I use this modern reformulation to shed light on two recent debates: (1) why is technical change often skill biased, and why has it become more skill biased during recent decades? (2) What is the role of human capital differences in accounting for income differences across countries? Interestingly, an application of this modern reformulation to these debates also reiterates some of the insights of another important paper by Phelps, Nelson and Phelps (1966). Keywords: Biased technical change, endogenous technical change, factor distribution of income, growth, innovation, skill-biased technical change, and technology.

We construct a simple model where political elites may block technological and institutional development, because of a "political replacement effect." Innovations often erode elites' incumbency advantage, increasing the likelihood that they will be replaced. Fearing replacement, political elites are unwilling to initiate change, and may even block economic development. We show that elites are unlikely to block development when there is a high degree of political competition, or when they are highly entrenched. It is only when political competition is limited and also their power is threatened that elites will block development. We also show that such blocking is more likely to arise when political stakes are higher, and that external threats may reduce the incentives to block. We argue that this model provides an interpretation for why Britain, Germany and the U.S. industrialized during the nineteenth century, while the landed aristocracy in Russia and Austria-Hungary blocked development. Keywords: Political Economy, Institutions, Development, Industrialization. JEL Classification: H2, N10, N40, O1, O3, O4.

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Most economic analyses presume that there are limited differences in the prior beliefs of individuals, an assumption most often justified by the argument that sufficient common experiences and observations will eliminate disagreements. We investigate this claim using a simple model of Bayesian learning. Two individuals with different priors observe the same infinite sequence of signals about some underlying parameter. Existing results in the literature establish that when individuals are certain about the interpretation of signals, under very mild conditions there will be asymptotic agreement -- their assessments will eventually agree. In contrast, we look at an environment in which individuals are uncertain about the interpretation of signals, meaning that they have non-degenerate probability distributions over the conditional distribution of signals given the underlying parameter. When priors on the parameter and the conditional distribution of signals have full support, we prove the following results: (1) Individuals will never agree, even after observing the same infinite sequence of signals. (2) Before observing the signals, they believe with probability 1 that their posteriors about the underlying parameter will fail to converge. (cont.) (3) Observing the same sequence of signals may lead to a divergence of opinion rather than the typically-presumed convergence. We then characterize the conditions for asymptotic agreement under "approximate certainty" - i.e., as we look at the limit where uncertainty about the interpretation of the signals disappears. When the family of probability distributions of signals given the parameter has "rapidly-varying tails" (such as the normal or the exponential distributions), approximate certainty restores asymptotic agreement. However, when the family of probability distributions has "regularly-varying tails" (such as the Pareto, the log-normal, and the t-distributions), asymptotic agreement does not obtain even in the limit as the amount of uncertainty disappears. Lack of common priors has important implications for economic behavior in a range of circumstances. We illustrate how the type of learning outlined in this paper interacts with economic behavior in various different situations, including games of common interest, coordination, asset trading and bargaining. Keywords: asymptotic disagreement, Bayesian learning, merging of opinions. JEL Classifications: C11, C72, D83.

The French Revolution of 1789 had a momentous impact on neighboring countries. The French Revolutionary armies during the 1790s and later under Napoleon invaded and controlled large parts of Europe. Together with invasion came various radical institutional changes. French invasion removed the legal and economic barriers that had protected the nobility, clergy, guilds, and urban oligarchies and established the principle of equality before the law. The evidence suggests that areas that were occupied by the French and that underwent radical institutional reform experienced more rapid urbanization and economic growth, especially after 1850. There is no evidence of a negative effect of French invasion. Our interpretation is that the Revolution destroyed (the institutional underpinnings of) the power of oligarchies and elites opposed to economic change; combined with the arrival of new economic and industrial opportunities in the second half of the 19th century, this helped pave the way for future economic growth. The evidence does not provide any support for several other views, most notably, that evolved institutions are inherently superior to those 'designed'; that institutions must be 'appropriate' and cannot be 'transplanted'; and that the civil code and other French institutions have adverse economic effects. Keywords: institutions, civil code, guilds, democracy, oligarchy, political economy. JEL Classifications: I10, O40, J11.

"We present a tractable framework for the analysis of the relationship between contract incompleteness, technological complementarities and the division of labor. In the model economy, a firm decides the division of labor and contracts with its worker-suppliers on a subset of activities they have to perform. Worker-suppliers choose their investment levels in the remaining activities anticipating the ex post bargaining equilibrium. We show that greater contract incompleteness reduces both the division of labor and the equilibrium level of productivity given the division of labor. The impact of contract incompleteness is greater when the tasks performed by different workers are more complementary. We also discuss the effect of imperfect credit markets on the division of labor and productivity, and study the choice between the employment relationship versus an organizational form relying on outside contracting. Finally, we derive the implications of our framework for productivity differences and comparative advantage across countries"--National Bureau of Economic Research web site.

The economics profession has made considerable progress in understanding the increase in wage inequality in the U.S. and the UK over the past several decades, but currently lacks a consensus on why inequality did not increase, or increased much less, in (continental) Europe over the same time period. I review the two most popular explanations for these differential trends: that relative supply of skills increased faster in Europe, and that European labor market institutions prevented inequality from increasing. I argue that these two explanations go some way towards accounting for the differential cross-country inequality trends, but do not provide an entirely satisfactory explanation. In addition, it appears that relative demand for skills increased differentially across countries. Motivated by this reasoning, I develop a simple theory where labor market institutions creating wage compression in Europe also encourage more investment in technologies increasing the productivity of less-skilled workers, thus implying less skill-biased technical change in Europe than in the U.S. Keywords: Relative Supply of Skills, Returns to Education, Skill-Biased Technical Change, Technology Adoption, Wage Compression, Wage Inequality. JEL Classification: J30, J31.

This paper evaluates the importance of "property rights institutions," which protect citizens against expropriation by the government and powerful elites, and "contracting institutions," which enable private contracts between citizens. We exploit exogenous variation in both types of institutions driven by colonial history, and document strong first-stage relationships between property rights institutions and the determinants of European colonization strategy (settler mortality and population density before colonization), and between contracting institutions and the identity of the colonizing power. Using this instrumental variables approach, we find that property rights institutions have a first-order effect on long-run economic growth, investment, and financial development. Contracting institutions appear to matter only for the form of financial intermediation. A possible explanation for this pattern is that individuals often find ways of altering the terms of their formal and informal contracts to avoid the adverse effects of contracting institutions, but are unable to do so against the risk of expropriation. Keywords: Contracts, Economic Growth, Financial Development, Institutions, Law and Finance, Legal Formalism, Legal Origin, Political Economy, Politics, Property Rights. JEL Classification: E44, G18, K00, N20, P16, P17.