Working papers results

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.

We present a new model of money management, in which investors delegate portfolio management to professionals based not only on performance, but also on trust. Trust in the manager reduces an investor' perception of the riskiness of a given investment, and allows managers to charge higher fees to investors who trust them more. Money managers compete for investor funds by setting their fees, but because of trust the fees do not fall to costs. In the model, 1) managers consistently underperform the market net of fees but investors still prefer to delegate money management to taking risk on their own, 2) fees involve sharing of expected returns between managers and investors, with higher fees in riskier products, 3) managers pander to investors when investors exhibit biases in their beliefs, and do not correct misperceptions, and 4) despite long run benefits from better performance, the profits from pandering to trusting investors discourage managers from pursuing contrarian strategies relative to the case with o trust. We show how trust-mediated money management renders arbitrage less effective, and may help destabilize financial markets.

We present a theory of context-dependent choice in which a consumer's attention is drawn to salient attributes of goods, such as quality or price. An attribute is salient for a good when it stands out among the good's attributes, relative to that attribute's average level in the choice set (or generally, the evoked set). Consumers attach disproportionately high weight to salient attributes and their choices are tilted toward goods with higher quality/price ratios. The model accounts for a variety of disparate evidence, including decoy effects, context-dependent willingness to pay, and large shifts in demand in response to price shocks.

We present a model of sovereign debt in which, contrary to conventional wisdom, government defaults are costly because they destroy the balance sheets of domestic banks. In our model, better financial institutions allow banks to be more leveraged, thereby making them more vulnerable to sovereign defaults. Our predictions: government defaults should lead to declines in private credit, and these declines should be larger in countries where financial institutions are more developed and banks hold more government bonds. In these same countries, government defaults should be less likely. Using a large panel of countries, we find evidence consistent with these predictions.

We conduct a geographically and temporally disaggregated empirical analysis of civil conflict at the sub-national level in Africa over the period 1997-2011. Our units of observation are cells of 1 degree of latitude by 1 degree of longitude. We exploit within-year variation in the timing of weather shocks and in the growing season of different crops, as well as spatial variation in crop cover, to construct an original measure of shocks that are relevant for agricultural production. Employing a new drought index we show that negative climate shocks which occur during the growing season of the main crop cultivated in the cell have a sizeable and persistent effect on conflict incidence. We also use state-of-the-art spatial econometric techniques to test for the presence of temporal and spatial spillovers in conflict, and we find both to be sizeable and highly statistically significant. Exploiting variation in the type of conflict episode, we find that the impact of climate shocks on conflict is particularly significant when focusing on outcomes such as battles and violence against civilians. Our estimates can be used to predict how future warming scenarios affect the prevalence and diffusion of conflict.

I show that labor-tying (being in a labor contract where the employer also acts as an insurance-provider) is an important channel through which the poor in rural Bangladesh insure themselves against risks. Using a theoretical framework adapted from Bardhan (1983), I analyze the effects of an exogenous increase in the outside options of poor women (through an improvement in their self-employment opportunities) on their and their spouses' participation in tied labor, as well as the general equilibrium effects of the treatment on the terms of the labor contracts in the village. I find that treated women and their spouses are less likely to be in tied-labor contracts. Their wages increase through two channels: (a) due to the switch from tied to casual labor contracts (b) through the general equilibrium effects in the village labor market. Furthermore, I find that the treated households form reciprocal transfer links with wealthier households in the village. These findings imply that poor households may be involved in second-best labor contracts to insure themselves against risks. When their self-employment opportunities improve, they break these ties and move to greater reliance on reciprocal transfer arrangements.