Knowledge that Transforms

We evaluate reforms to the U.S. tax system in a life cycle set-up with heterogeneous married and single households and with an operative extensive margin in labour supply. We restrict our model with observations on gender and skill premia, labour-force participation of married females across skill groups, children, and the structure of marital sorting. We concentrate on two revenue-neutral tax reforms: a proportional income tax and a reform in which married individuals file taxes separately (separate filing). Our findings indicate that tax reforms are accompanied by large increases in labour supply that differ across demographic groups, with the bulk of the increase coming from married females. Under a proportional income tax reform, married females account for more than 50% of the changes in hours across steady states, while under separate filing reform, married females account for all the change in hours.

A search-theoretic model of the retail market for illegal drugs is developed. Trade occurs in bilateral, potentially long-lived matches between sellers and buyers. Buyers incur search costs when experimenting with a new seller. Moral hazard is present because buyers learn purity only after a trade is made. This model is consistent with some new stylized facts about the drugs market, and it is informative for policy design. The effectiveness of different enforcement strategies is evaluated, including some novel ones that leverage the moral hazard present in the market.

This paper addresses two questions: What accounts for the gender gap in labour-market outcomes? What are the driving forces behind the changes in the gender labour-market outcomes over the period 1968–1997? It formulates a dynamic general equilibrium model of labour supply, occupational sorting, and human-capital accumulation in which gender discrimination and an earnings gap arise endogenously. It uses this model to quantify the driving forces behind the decline in the gender earnings gap and the increase in female labour-force participation, the proportion of women working in professional occupations, and hours worked. It finds that labour-market experience is the most important factor explaining the gender earnings gap. In addition, statistical discrimination accounts for a large fraction of the observed gender earnings gap and its decline. It also finds that a large increase in aggregate productivity in professional occupations plays a major role in the increase in female labour-force participation, number of hours worked, and the proportion of females working in professional occupations. Although of less importance, demographic changes account for a substantial part of the increase in female labour-force participation and hours worked, whereas home production technology shocks do not.

Starting in the 1970's, wage inequality and the number of hours worked by employed U.S. prime-age male workers have both increased. We argue that these two facts are related. We use a labour market model with on-the-job search where by working longer hours individuals acquire greater skills. Since job candidates are ranked by productivity, greater skills not only increase worker's productivity in the current job but also help the worker to obtain better jobs. When job offers become more dispersed, wage inequality increases and workers work longer hours to obtain better jobs. As a result, average hours per worker in the economy increase. This mechanism accounts for around two-thirds of the increase in hours observed in data. Part of the increase is inefficient since workers obtain better jobs at the expense of other workers competing for the same jobs.

This paper studies gender interactions within hierarchical organizations using a large data set on the duration of Italian municipal governments elected between 1993 and 2003. A municipal government can be viewed as a hierarchy, whose stability over time depends on the degree of cooperation between and within ranks. We find that in municipalities headed by female mayors, the probability of early termination of the legislature is higher. This result persists and becomes stronger when we control for municipality fixed effects as well as for non-random sorting of women into municipalities using regression discontinuity in gender-mixed electoral races decided by a narrow margin. The likelihood that a female mayor survives until the end of her term is lowest when the council is entirely male and in regions with less favourable attitudes towards working women. This evidence is suggestive that group dynamics are an important factor in driving the gender difference. Other interpretations receive less support in the data. Our results may provide an alternative explanation for the underrepresentation of women in leadership positions.

We investigate the empirical content of the Nash solution to two-player bargaining games. The bargaining environment is described by a set of variables that may affect agents' preferences over the agreement sharing, the status quo outcome, or both. The outcomes ( i.e. whether an agreement is reached, and if so the individual shares) and the environment (including the size of the pie) are known, but neither are the agents' utilities nor their threat points. We consider both a deterministic version of the model in which the econometrician observes the shares as deterministic functions of the variables under consideration and a stochastic one in which because of latent disturbances only the joint distribution of incomes and outcomes is recorded. We show that in the most general framework any outcome can be rationalized as a Nash solution. However, even mild exclusion restrictions generate strong implications that can be used to test the Nash bargaining assumption. Stronger conditions further allow to recover the underlying structure of the bargaining, and in particular, the cardinal representation of individual preferences in the absence of uncertainty. An implication of this finding is that empirical works entailing Nash bargaining could (and should) use much more general and robust versions than they usually do.

We study strategic information transmission in an organization consisting of an infinite sequence of individual decision-makers. Each decision-maker chooses an action and receives an informative but imperfect signal of the once-and-for-all realization of an unobserved state. The state affects all individuals' preferences over present and future decisions. Decision-makers do not directly observe the realized signals or actions of their predecessors. Instead, they must rely on cheap-talk messages in order to accumulate information about the state. Each decision-maker is therefore both a receiver of information with respect to his decision and a sender with respect to all future decisions. We show that if preferences are not perfectly aligned, “full learning” equilibria—ones in which the individuals' posterior beliefs eventually place full weight on the true state—do not exist. This is so both in the case of private communication, in which each individual only hears the message of his immediate predecessor, and in the case of public communication, in which a decision-maker hears the message of all his predecessors. Surprisingly, in the latter case full learning may be impossible even in the limit as all members of the organization become perfectly patient. We also consider the case where all individuals have access to a mediator who can work across time periods arbitrarily far apart. In this case, full learning equilibria exist.

I allow trading horizon heterogeneity across groups in a standard differential information model of a financial market. This approach can explain the well-established phenomenon that, after a public announcement, trading volume increases, more private information is incorporated into prices and volatility increases. In such environments, public information has the important secondary role of helping agents learn about the information of other agents. Therefore, whenever the correlation between the private information of different groups is sufficiently low, a public announcement increases disagreement among short-horizon traders regarding the expected selling price even as it decreases disagreement about the fundamental value of the asset. Additional testable implications are also suggested.

The game-theoretic literature on collusion has been hard pressed to explain why a cartel should engage in price wars, without resorting to either impatience, symmetry restrictions, inability to communicate, or failure to optimize. This paper introduces a new explanation that relies on none of these assumptions: if the cartel's member firms have private information about their costs, price wars can be optimal in the face of complexity. Specifically, equilibria that are robust to pay-off irrelevant disruptions of the information environment generically cannot attain or approximate efficiency. An optimal robust equilibrium must allocate market shares inefficiently and may call for price wars under certain conditions. For a two-firm cartel, cost interdependence is a sufficient condition for price wars to arise in an optimal robust equilibrium. That optimal equilibria are inefficient generically applies not only to collusion games but also to the entire separable pay-off environment—a class that includes most typical economic models.

Drawing on uncommonly rich and representative data from the Colombian manufacturing census, this paper documents new empirical relationships between input prices, output prices, and plant size and proposes a model of endogenous input and output quality choices by heterogeneous firms to explain the observed patterns. The key empirical facts are that, on average within narrowly defined sectors, (1) larger plants charge more for their outputs and (2) larger plants pay more for their material inputs. The latter fact generalizes the well-known positive correlation between plant size and wages. Similar correlations hold between prices and export status. We show that the empirical patterns are consistent with a parsimonious extension of the Melitz (2003, “The Impact of Trade on Intra-Industry Reallocations and Aggregate Industry Productivity,” Econometrica, 71, 1695–1725) framework to include endogenous choice of input and output quality. Using a measure of the scope for quality differentiation from Sutton (1998, Technology and Market Structure: Theory and History. Cambridge: MIT Press), we show that differences across sectors in the relationships between prices and plant size are consistent with our model. Available evidence suggests that differences in observable measures of market power do not provide a complete explanation for the empirical patterns. We interpret the results as supportive of the hypothesis that quality differences of both inputs and outputs play an important role in generating the price–plant size correlations.