Working papers results

This paper formulates a general theory of how political unrest influences public policy. Political unrest is motivated by emotions. Individuals engage in protests if they are aggrieved and feel that they have been treated unfairly. This reaction is predictable because individuals have a con sistent view of what is fair. This framework yields novel insights about the sources of political influence of different groups in society. Even if the government is benevolent and all groups have access to the same technology for political participation, equilibrium policy can be distorted. Individuals form their view of what is fair taking into account the current state of the world. If fewer aggregate resources are available, individuals accept a lower level of welfare. This resignation effect in turn induces a benevolent government to procrastinate unpleasant policy choices.

This paper tests the broadly adopted assumption that people apply a single discount rate to the utility from different sources of consumption. Using unique data from two surveys conducted in rural Uganda including both hypothetical and real choices over different goods, the paper elicits time preferences from approximately 2,400 subjects. The data reject the null of equal discount rates across goods under a number of different modeling assumptions. These results have important theoretical and policy implications. For instance, they provide support for the idea that time-inconsistent behaviors and a corresponding demand for commitment can be observed even if individuals do not exhibit horizon-specific discounting. In addition, good-specific discounting, under certain conditions, can explain the persistence of poverty and low savings by the poor. The paper presents evidence that these conditions are satisfied in the context under study by showing that the share of expenditures on those goods with higher discount rates is decreasing with income.

In one-good international macro models with nondiversifiable labor income risk, country portfolios are heavily biased toward foreign assets. The fact that the opposite pattern of diversification is observed empirically constitutes the international diversification puzzle. This paper embeds a portfolio choice decision in a two-country, two-good version of the stochastic growth model. In this environment, which is a workhorse for international business cycle research, equilibrium country portfolios can be characterized in closed form. Portfolios are biased toward domestic assets, as in the data. Home bias arises because endogenous international relative price
uctuations make domestic assets a good hedge against labor income risk. Evidence from developed economies in recent years is qualitatively and quantitatively consistent with the mechanisms highlighted by the theory.

This paper addresses the following questions. Is there evidence of contagion in the Eurozone? To what extent do sovereign risk and the vulnerability to contagion depend on fundamentals as opposed to a country's 'credibility'? We look at the empirical evidence on EU sovereigns CDS spreads and estimate an econometric model where the crucial role is played by time varying parameters. We model CDS spread changes at country level as reecting three different factors: a Global sovereign risk factor, a European sovereign risk factor and a Financial intermediaries risk factor. Our main ndings are as follows. First, while the US subprime crisis affects all European sovereign risks, the Greek crisis is largely a matter concerning the Euro Zone. Second, differences in vulnerability to contagion in the Eurozone are remarkable: after the Greek crisis the core Eurozone members become less vulnerable to EUZ contagion, possibly due to a safe-heaven effect, while peripheric countries become more vulnerable. Third, market fundamentals go a long way in explaining these differences: they jointly explain between 54 and 80% of the cross-country variation in idiosyncratic risks and in the vulnerability to contagion, largely supporting the 'wake-up calls' hypothesis suggesting that market participats bocome more wary of market fundamentals during finacial crises.

We consider the problem of selling a firm to a single buyer. The magnitude of the post-sale cash flow rights (v) as well as the benefits of control (b) are the buyer's private information. In contrast to research that assumes the private information of the buyer is one-dimensional, the optimal mechanism is a menu of tuples of cashequity mixtures. We provide sufficient conditions on the joint distribution of v and b such that the optimal mechanism takes one of the following forms: i) a take-it or leave-it offer for the smallest fraction of the company that facilitates the transfer of control, or ii) a take-it or leave-it offer for all the shares of the company. We also identify a sufficient condition for the seller to extract the full value, v, per share so that the buyer earns information rents only on the private benefits of control.

This paper analyses the effect of skilled migration on two measures of innovation, patenting and citations of scientific publications, in a panel of 20 European countries. Skilled migrants positively contribute to the knowledge formation in host countries as they add to the pool of skills in destination markets. Moreover, they positively affect natives' productivity, as new ideas are likely to arise through the interaction of diverse cultures and diverse approaches in problem solving. The empirical findings we present support this prediction. Greater diversity in the skilled professions are associated with higher levels of knowledge creation, measured either by the number of patents applied for through the Patent Cooperation Treaty or by the number of citations to published articles. This finding is robust to the use of different proxies for both the explanatory variables and the diversity index in the labour force. Specifically, we first measure diversity with a novel indicator which uses information on the skill level of foreigners' occupations. We then check our results by following the general literature, which measures skills by looking at the foreigners' level of education. We show that cultural diversity consistently increases the innovation performance of European Countries.

How should a decision-maker assess the potential of an investment when a group of experts provides strongly divergent estimates on its expected payoff? To address this question, we propose and analyze a variant of the well-studied α-maxmin model in decision theory. In our framework, and consistent to the paper's empirical focus on R&D investment, experts' subjective probability distributions are allowed to be action-dependent. In addition, the decision maker constrains the sets of priors to be considered in accordance with ethical considerations and/or operational protocols. Using tools from convex and conic optimization, we are able to establish a number of analytical results including a closed-form expression of our model's value function, a thorough investigation of its differentiability properties, and necessary conditions for optimal investment. We apply our framework to original data from a recent expert elicitation survey on solar technology. The analysis suggests that more aggressive investment in solar technology R&D is likely to yield significant dividends even, or rather especially, after taking ambiguity into account.

We study optimal taxation of savings in an economy where agents face self-control problems and are allowed to be partially naive. We assume that the severity of self-control problems changes over the life-cycle. We focus on quasihyperbolic discounting with constant elasticity of intertemporal substitution utility functions and linear Markov equilibria. We derive explicit formulas for optimal taxes that implement the efficient allocation. We show that if agents' ability to self-control increases concavely with age, then savings should be subsidized and the subsidy should decrease with age. We also show that allowing for age-dependent self-control problems creates large effects on the level of optimal subsidies, while optimal taxes are not very sensitive to the level of sophistication.

Several recent papers have proposed recursive Lagrangian-basedmethods for solving dynamic contracting problems. Thesemethods give rise to Bellman operators that incorporate either a dual inf-sup or a saddle point operation. We give conditions that ensure the Bellman operator implied by a dual recursive formulation is contractive.

This paper analyses contract cancellation and product return policies in markets in which sellers advise customers about the suitability of their offering. When customers are fully rational, it is optimal for sellers to offer the right to cancel or return on favorable terms. A generous return policy makes the seller's 'cheap talk' at the point of sale credible. This observation provides a possible explanation for the excess refund puzzle and also has implications for the management of customer reviews. When customers are credulous, instead, sellers have an incentive to set unfavorable terms to exploit the inflated beliefs they induce in their customers. The imposition of a minimum statutory standard improves welfare and consumer surplus when customers are credulous. In contrast, competition policy reduces contractual inefficiencies with rational customers, but it is not effective with credulous customers.