The Causal effect of education on aggregate income

Empirical studies assume that the macro Mincer return on schooling is con- stant across countries. Using a large sample of countries this paper shows that countries with a better quality of education have on average relatively higher macro Mincer coeficients. As rich countries have on average better educational quality, differences in human capital between countries are larger than has been typically assumed in the development accounting literature. Consequently, factor accumulation explains a considerably larger share of income differences across countries than what is usually found.

Climate change in the Atlantic Ocean since the 1940's and the effects on the global climate

En aquest projecte s’ha estudiat la relació entre els canvis en les temperatures superficials de l’Oceà Atlàntic i els canvis en la circulació atmosfèrica en el segle XX. Concretament s’han analitzat dos períodes de estudi: el primer des del 1940 al 1960 i el segon des del 1980 fins al 2000. S’ha posat especial interès en les anomalies en les temperatures superficials del mar en la regió tropical de l’Oceà Atlàntic i la possible interconnexió amb els canvis climàtics observats i predits. Per a la realització de l’estudi s’han dut a terme una sèrie d’experiments utilitzant el model climàtic elaborat a la universitat d’UCLA (UCLA‐AGCM model). Els resultats obtinguts han estat analitzats en forma de mapes i figures per a cada variable d’estudi. També s’ha fet una comparació entre els resultats obtinguts i altres trobats en altres treballs publicats sobre el mateix tema de recerca. Els resultats obtinguts són molt amplis i poden tenir diverses interpretacions. Tot i així algunes de les conclusions a les quals s’ha arribat són: les diferències més significatives per a les variables estudiades i trobades a partir dels resultats obtinguts del model per als dos períodes d’estudi són en els mesos d’hivern i a la zona dels tròpics; concretament a parts del nord de sud Amèrica i a parts del nord d’Àfrica. S’han trobat també canvis significatius en els patrons de precipitació sobre aquestes mateixes zones. També s’ha observant un moviment cap al nord de la zona d’interconvergència tropical i pot ser degut a l’anòmal gradient trobat a la zona equatorial en les temperatures superficial de l’Oceà. Tot i així per a una definitiva discussió i conclusions sobre els resultats dels experiments, seria necessari un estudi més ampli i profund.

Modelling the cooling of concrete by piped water

Piped water is used to remove hydration heat from concrete blocks during construction. In this paper we develop an approximate model for this process. The problem reduces to solving a one-dimensional heat equation in the concrete, coupled with a first order differential equation for the water temperature. Numerical results are presented and the effect of varying model parameters shown. An analytical solution is also provided for a steady-state constant heat generationmodel. This helps highlight the dependence on certain parameters and can therefore provide an aid in the design of cooling systems.

A Sensitivity analysis of poverty definitions

We conduct a sensitivity analysis of several estimators related to household income, to explore how some details of the definitions of the variables concerned influence the values of the common estimates, such as the mean, median and (poverty) rates. The purpose of this study is to highlight that some of the operational definitions entail an element of arbitrariness which leaves an undesirable stamp on the inferences made. The analyses use both a cross-sectional and a longitudinal (panel) component of the EU-SILC database.

On Strategy-proofness and symmetric single-peakedness

We characterize the class of strategy-proof social choice functions on the domain of symmetric single-peaked preferences. This class is strictly larger than the set of generalized median voter schemes (the class of strategy-proof and tops-only social choice functions on the domain of single-peaked preferences characterized by Moulin (1980)) since, under the domain of symmetric single-peaked preferences, generalized median voter schemes can be disturbed by discontinuity points and remain strategy-proof on the smaller domain. Our result identifies the specific nature of these discontinuities which allow to design non-onto social choice functions to deal with feasibility constraints.

The Disadvantage of winning an election

This paper analyzes the problem that an incumbent faces during the legislature when deciding how to react to popular initiatives or policy proposals coming from different sources. We argue that this potential source of electoral disadvantage that the incumbent obtains after being elected can jeopardize the reelection possibilities of the incumbent. We analyze the decision of the incumbent when facing reelection and we characterize the conditions under which the advantages that the incumbent obtains can overcome the disadvantages. Finally, we use the results of this analysis to discuss some implications of the use of mechanisms of direct democracy like referenda and popular assemblies on electoral competition.

Work values, endogenous sentiments and redistribution

We examine the interactions between individual behavior, sentiments and the social contract in a model of rational voting over redistribution. Agents have moral "work values". Individuals' self-esteem and social consideration of others are endogenously determined comparing behaviors to moral standards. Attitudes toward redistribution depend on self-interest and social preferences. We characterize the politico-economic equilibria in which sentiments, labor supply and redistribution are determined simultaneously. The equilibria feature different degrees of "social cohesion" and redistribution depending on pre-tax income inequality. In clustered equilibria the poor are held partly responsible for their low income since they work less than the moral standard and hence redistribution is low. The paper proposes a novel explanation for the emergence of different sentiments and social contracts across countries. The predictions appear broadly in line with well-documented differences between the United States and Europe.

Preference intensities and risk aversion in school choice: a laboratory experiment

We experimentally investigate in the laboratory two prominent mechanisms that are employed in school choice programs to assign students to public schools. We study how individual behavior is influenced by preference intensities and risk aversion. Our main results show that (a) the Gale-Shapley mechanism is more robust to changes in cardinal preferences than the Boston mechanism independently of whether individuals can submit a complete or only a restricted ranking of the schools and (b) subjects with a higher degree of risk aversion are more likely to play "safer" strategies under the Gale-Shapley but not under the Boston mechanism. Both results have important implications for the efficiency and the stability of the mechanisms.

Longer-term impacts of mentoring, educational services, and incentives to learn: evidence from a randomized trial in the United States

This paper is the first to use a randomized trial in the US to analyze the short- and long-term educational and employment impacts of an afterschool program that offered disadvantaged high-school youth: mentoring, educational services, and financial rewards with the objective to improve high-school graduation and postsecondary schooling enrollment. The short-term hefty beneficial average impacts quickly faded away. Heterogeneity matters. While encouraging results are found for younger youth, and when the program is implemented in relatively small communities of 9th graders; detrimental longlived outcomes are found for males, and when case managers are partially compensated by incentive payments and students receive more regular reminders of incentives.

Strategic mass killings

Since World War II there have been about fifty episodes of large-scale mass killings of civilians and massive forced displacements. They were usually meticulously planned and independent of military goals. We provide a model where conflict onset, conflict intensity and the decision to commit mass killings are all endogenous, with two main goals: (1) to identify the key variables and situations that make mass killings more likely to occur; and (2) to distinguish conditions under which mass killings and military conflict intensity reinforce each other from situations where they are substitute modes of strategic violence. We predict that mass killings are most likely in societies with large natural resources, significant proportionality constraints for rent sharing, low productivity and low state capacity. Further, massacres are more likely in a civil than in an interstate war, as in the latter group sizes matter less for future rents. In non polarized societies there are asymmetric equilibria with only the larger group wanting to engage in massacres. In such settings the smaller group compensates for this by fighting harder in the first place. In this case we can talk of mass killings and fighting efforts to be substitutes. In contrast, in polarized societies either both or none of the groups can be ready to do mass killings in case of victory. Under the "shadow of mass killings" groups fight harder. Hence, in this case massacres and fighting are complements. We also present novel empirical results on the role of natural resources in mass killings and on what kinds of ethnic groups are most likely to be victimized in massacres and forced resettlements, using group level panel data.

Strategy-proof social choice

This paper surveys the literature on strategy-proofness from a historical perspective. While I discuss the connections with other works on incentives in mechanism design, the main emphasis is on social choice models. This article has been prepared for the Handbook of Social Choice and Welfare, Volume 2, Edited by K. Arrow, A. Sen and K. Suzumura

Mentoring, educational services, and economic incentives longer-term evidence on risky behaviors from a randomized trial

This paper is the first to use a randomized trial in the US to analyze the short- and long- term impacts of an afterschool program that offered disadvantaged high-school youth: mentoring, educational services, and financial rewards to attend program activities, complete high-school and enroll in post-secondary education on youths' engagement in risky behaviors, such as substance abuse, criminal activity, and teenage childbearing. Outcomes were measured at three different points in time, when youths were in their late-teens, and when they were in their early- and their latetwenties. Overall the program was unsuccessful at reducing risky behaviors. Heterogeneity matters in that perverse effects are concentrated among certain subgroups, such as males, older youths, and youths from sites where youths received higher amount of stipends. We claim that this evidence is consistent with different models of youths' behavioral response to economic incentives. In addition, beneficial effects found in those sites in which QOP youths represented a large fraction of the entering class of 9th graders provides hope for these type of programs when operated in small communities and supports the hypothesis of peer effects.

Civil war and foreign influence

We study a symmetric information bargaining model of civil war where a third (foreign) party can affect the probabilities of winning the conflict and the size of the post conflict spoils. We show that the possible alliance with a third party makes peaceful agreements difficult to reach and might lead to new commitment problems that trigger war. Also, we argue that the foreign party is likely to induce persistent informational asymmetries which might explain long lasting civil wars. We explore both political and economic incentives for a third party to intervene. The explicit consideration of political incentives leads to two predictions that allow for identifying the influence of foreign intervention on civil war incidence. Both predictions are confirmed for the case of the U.S. as a potential intervening nation: (i) civil wars around the world are more likely under Republican governments and (ii) the probability of civil wars decreases with U.S. presidential approval rates.

Cultural leaders and the clash of civilizations

This article builds a micro founded model of the clash of cultures. The clash is defined as the parent's fear of a trait change by their child in an overlapping generations model with intergenerational transmission of cultural traits. The extent of the clash is manipulated by cultural leaders who benefit from the cultural education effort by parents. We identify three channels through which the leaders can affect the clash of cultures: (i) by providing beneficial cultural values, (ii) by claims of cultural superiority and (iii) by cultural alienation, i.e. by inducing cultural dislike towards their own group. We show that all three channels can be in the leader's interest but channels (ii) and (iii) reduce the utility of the leader's goup members. This hints to a strong conflict of interest within groups - between the population at large and the benefactors of radicalization. We further show how the use of alienation relates to the economic opportunities available to a group.

Ethnicity and conflict : an empirical study

This paper examines the impact of ethnic divisions on conflict. The analysis relies on a theoretical model of conflict (Esteban and Ray, 2010) in which equilibrium conflict is shown to be accurately described by a linear function of just three distributional indices of ethnic diversity: the Gini coefficient, the Hirschman-Herfindahl fractionalization index, and a measure of polarization. Based on a dataset constructed by James Fearon and data from Ethnologue on ethno-linguistic groups and the "linguistic distances" between them, we compute the three distribution indices. Our results show that ethnic polarization is a highly significant correlate of conflict. Fractionalization is also significant in some of the statistical exercises, but the Gini coefficient never is. In particular, inter-group distances computed from language and embodied in polarization measures turn out to be extremely important correlates of ethnic conflict.