Research

Recent Publications
✧ Publications by Topic: Climate change÷Political Economy÷Welfare Economics÷Other

Recent publications

"Nash versus Kant: A game-theoretic analysis of childhood vaccination behavior"
De Donder, Philippe, Humberto Llavador, Stefan Penczynski, John E. Roemer, and Roberto Vélez. Working paper. June 2023. [PDF]

Abstract: The vaccination game exhibits positive externalities. The standard game-theoretic approach assumes that parents make decisions according to the Nash protocol, which is individualistic and non-cooperative. However, in more solidaristic societies, parents may behave cooperatively, optimizing according to the Kantian protocol, in which the equilibrium is efficient. We develop a random utility model of vaccination behavior and prove that the equilibrium coverage rate is larger with the Kant protocol than with the Nash one. Using survey data collected from six countries, we calibrate the parameters of the vaccination game, compute both Nash equilibrium and Kantian equilibrium profiles, and compare them with observed vaccination behavior. We find evidence that parents demonstrate cooperative behavior in all six countries. We argue that the existence of positive externalities has fostered a social norm, leading to higher vaccination rates than predicted by individualistic decision-making, and that the Kantian equilibrium offers one precise version of such social norm. The study highlights the importance of cooperation and social norms in shaping vaccination behavior and underscores the need to consider these factors in public health interventions.

​​"Global Unanimity Agreement on the Carbon Budget" (2022) Llavador, Humberto, John E. Roemer and Thomas Stoerk. Cuadernos Económicos 104: 9-29. doi: 10.32796/cice.2022.104.7491 [PDF]

Abstract: This paper analyzes a stylized model of the global economy in which countries must agree on the carbon budget while the decision on the level of carbon emissions is decentralized, with firms treating their emissions as a production input for which a uniform price is charged. The revenue accumulates in a global fund and is returned to global citizens according to national shares that are announced ex ante. The vector of country shares for the distribution of the carbon revenue assures  that  countries  agree  by  unanimity  on  the  carbon  budget.  The  equilibrium  exhibits  the  following desired features: (1) the global emissions level is set by unanimous agreement; (2) the demand to emit carbon is decentralized and, hence, there is no need to determine the distribution of permits; and (3) the equilibrium is Pareto efficient. We explore the implication of the model in an application based on RICE-2010.

"Inequality, Bipolarization, and Tax Progressivity" (2021) Oriol Carbonell-Nicolau and Humberto Llavador American Economic Journal: Microeconomics 13(4): 492–513. doi: 10.1257/mic.20190111

Abstract: The steady rise in income and wealth inequality in the last four decades, together with the evolution of a vanishing middle class, has raised concerns about potentially pernicious effects of these trends on social stability and economic growth. This paper evaluates the possibility of designing tax systems aimed at reducing income inequality and bipolarization. Using two fundamentally different metrics, we provide a unified foundation of tax progressivity whereby, roughly, taxes are progressive if and only if they are inequality reducing if and only if they are bipolarization reducing.

"The Planetary Wellbeing Initiative: Pursuing the Sustainable Development Goals in Higher Education" (2021) Antó, J.M.; Martí, J.L.; Casals, J.; Bou-Habib, P.; Casal, P.; Fleurbaey, M.; Frumkin, H.; Jiménez-Morales, M.; Jordana, J.; Lancelotti, C.; Llavador, H.; Mélon, L.; Solé, R.; Subirada, F.; Williams, A Sustainability 13, 3372. doi: 10.3390/su13063372

Abstract: We live in a time of pressing planetary challenges, many of which threaten catastrophic change to the natural environment and require massive and novel coordinated scientific and societal efforts on an unprecedented scale. Universities and other academic institutions have the opportunity and responsibility to assume a leading role in an era when the destiny of the planet is precisely in the hands of human beings. Drawing on the Planetary Health project promoted by the Rockefeller Foundation and The Lancet, Pompeu Fabra University launched in 2018 the Planetary Wellbeing Initiative, a long-term institutional strategy also animated by the United Nations Sustainable Development Goals (SDGs). Planetary Wellbeing might be defined as the highest attainable standard of wellbeing for human and non-human beings and their social and natural systems. Developing the potential of these new concepts involves a substantial theoretical and empirical effort in many different fields, all of them interrelated by the crosscutting challenges of global complexity, interdisciplinarity, and urgency. Close collaboration of science, humanities, and culture is more desperately needed now than ever before in the history of humankind.

​​"Elasticity Determinants of Inequality Reducing Income Taxation" (2021) Oriol Carbonell-Nicolau and Humberto Llavador. Journal of Economic Inequality 19:163-183 doi: 10.1111/0034-6527.00322

Abstract: The link between income inequality and progressive taxation has long been considered a fundamental normative foundation for income tax progressivity. This paper furnishes necessary and sufficient conditions on primitives, in terms of the elasticity of income with respect to ability, under which various subclasses of progressive taxes are inequality reducing. The distributional effects of progressive income taxation are decomposed into two conditions on the wage elasticity of income, the tax rate effect and the subsidy effect, each capturing different aspects of the transition between before-tax and after-tax income distributions. The results confer a degree of useful flexibility to the theory, in that they allow the analyst to expand the universe of consumer preferences by suitably restricting the set of marginal-rate progressive taxes. As an illustration of the results’ practical implications, we provide a precise characterization of the subclass of (progressive) taxes that are inequality reducing for the constant elasticity of substitution (CES) and the quasi-linear utility functions.

​​"Short-Term Effect of Air Pollution on Attention Function in Adolescents (ATENC!Ó): A Randomized Controlled Trial in High Schools in Barcelona, Spain" (2021) Gignac, F., J. Barrera-Gómez, C. Persavento, C. Solé, E. Tena, M. López-Vicente, M. Foraster, F. Amato, A. Alastuey, X. Querol, H. Llavador, J. Apesteguia, J.i Júlvez, D. Couso, J. Sunyer, X. Basagaña. Environment International 156:106614 doi: 10.1016/j.envint.2021.106614

Abstract: We conducted a randomized controlled trial to assess whether air pollution in high schools can affect the attention processes of adolescents. We recruited a total of 2,123 adolescents (14-15 years old) in 33 high schools in Barcelona metropolitan area (Spain). In each school, adolescents from each class were randomly split into two equal-sized groups and assigned to two different classrooms. One classroom had an internal air cleaner (recirculation and filtration) and the other had the same device but without the filter (only recirculation). Students were masked to intervention allocation and had to complete several computerized activities for 1.5 hours, including an attention test (Flanker task) to be performed at baseline and at the end of the intervention. The response speed consistency, expressed as hit reaction time standard error (HRT-SE, in ms), was measured as the primary outcome. Analyses were conducted using conditional linear regressions with classroom as strata, adjusted for variables that may differ from one class to another such as temperature, humidity and carbon dioxide concentration. Average levels of PM 2.5 and black carbon throughout the 1.5 hours of experiment were 89% and 87%, respectively, lower in the classrooms with air cleaner than in the control classrooms. No differences were found in the median of HRT-SE between classrooms with cleaned air and normal air (percent change: 1.37%, 95% confidence interval: -2.81%, 5.56%). Sensitivity analyses with secondary attention outcomes resulted in similar findings.

Publications by topic
climate change ✧ political economy ✧ welfare economics ✧ other

Climate Change

​​"Global Unanimity Agreement on the Carbon Budget" (2022) Llavador, Humberto, John E. Roemer and Thomas Stoerk. Cuadernos Económicos 104: 9-29.
doi: 10.32796/cice.2022.104.7491 [PDF]

Abstract: This paper analyzes a stylized model of the global economy in which countries must agree on the carbon budget while the decision on the level of carbon emissions is decentralized, with firms treating their emissions as a production input for which a uniform price is charged. The revenue accumulates in a global fund and is returned to global citizens according to national shares that are announced ex ante. The vector of country shares for the distribution of the carbon revenue assures  that  countries  agree  by  unanimity  on  the  carbon  budget.  The  equilibrium  exhibits  the  following desired features: (1) the global emissions level is set by unanimous agreement; (2) the demand to emit carbon is decentralized and, hence, there is no need to determine the distribution of permits; and (3) the equilibrium is Pareto efficient. We explore the implication of the model in an application based on RICE-2010.

​​"Short-Term Effect of Air Pollution on Attention Function in Adolescents (ATENC!Ó): A Randomized Controlled Trial in High Schools in Barcelona, Spain" (2021) Gignac, F., J. Barrera-Gómez, C. Persavento, C. Solé, E. Tena, M. López-Vicente, M. Foraster, F. Amato, A. Alastuey, X. Querol, H. Llavador, J. Apesteguia, J.i Júlvez, D. Couso, J. Sunyer, X. Basagaña. Environment International 156:106614 doi: 10.1016/j.envint.2021.106614

Abstract: We conducted a randomized controlled trial to assess whether air pollution in high schools can affect the attention processes of adolescents. We recruited a total of 2,123 adolescents (14-15 years old) in 33 high schools in Barcelona metropolitan area (Spain). In each school, adolescents from each class were randomly split into two equal-sized groups and assigned to two different classrooms. One classroom had an internal air cleaner (recirculation and filtration) and the other had the same device but without the filter (only recirculation). Students were masked to intervention allocation and had to complete several computerized activities for 1.5 hours, including an attention test (Flanker task) to be performed at baseline and at the end of the intervention. The response speed consistency, expressed as hit reaction time standard error (HRT-SE, in ms), was measured as the primary outcome. Analyses were conducted using conditional linear regressions with classroom as strata, adjusted for variables that may differ from one class to another such as temperature, humidity and carbon dioxide concentration. Average levels of PM 2.5 and black carbon throughout the 1.5 hours of experiment were 89% and 87%, respectively, lower in the classrooms with air cleaner than in the control classrooms. No differences were found in the median of HRT-SE between classrooms with cleaned air and normal air (percent change: 1.37%, 95% confidence interval: -2.81%, 5.56%). Sensitivity analyses with secondary attention outcomes resulted in similar findings.

"The Planetary Wellbeing Initiative: Pursuing the Sustainable Development Goals in Higher Education" (2021).  Antó, J.M.; Martí, J.L.; Casals, J.; Bou-Habib, P.; Casal, P.; Fleurbaey, M.; Frumkin, H.; Jiménez-Morales, M.; Jordana, J.; Lancelotti, C.; Llavador, H.; Mélon, L.; Solé, R.; Subirada, F.; Williams, A Sustainability 13, 3372. doi: 10.3390/su13063372

Abstract: We live in a time of pressing planetary challenges, many of which threaten catastrophic change to the natural environment and require massive and novel coordinated scientific and societal efforts on an unprecedented scale. Universities and other academic institutions have the opportunity and responsibility to assume a leading role in an era when the destiny of the planet is precisely in the hands of human beings. Drawing on the Planetary Health project promoted by the Rockefeller Foundation and The Lancet, Pompeu Fabra University launched in 2018 the Planetary Wellbeing Initiative, a long-term institutional strategy also animated by the United Nations Sustainable Development Goals (SDGs). Planetary Wellbeing might be defined as the highest attainable standard of wellbeing for human and non-human beings and their social and natural systems. Developing the potential of these new concepts involves a substantial theoretical and empirical effort in many different fields, all of them interrelated by the crosscutting challenges of global complexity, interdisciplinarity, and urgency. Close collaboration of science, humanities, and culture is more desperately needed now than ever before in the history of humankind.

"North-South Convergence and the Allocation of CO2 Emissions" (2015). Humberto Llavador, John E. Roemer and Joaquim Silvestre. Climatic  Change 130(3):383-395. doi:10.1007/s10584-014-1227-8

Abstract: Mankind must cooperate to reduce GHG emissions to prevent a catastrophic rise in global temperature. How can the necessary costs of reducing GHG emissions be allocated across regions of the world, within the next few generations, and simultaneously address growth expectations and economic development? We postulate a two-region world and, based on sustainability and egalitarian criteria, calculate optimal paths in which a South, like China, and a North, like the United States, converge in welfare per capita to a path of sustained growth of 1% per year by 2080, while global CO2 emissions are restricted to the Representative Concentration Pathway RCP3-PD scenario: a conservative path that leads to the stabilization of concentrations under 450 ppm CO2, providing an expected temperature change not exceeding 2ºC. Growth expectations in the North and the South must be scaled back substantially, not only after 2080, but also in the transition period. Global negotiations to restrict emissions to an acceptably low level cannot succeed absent such an understanding. Feasible growth paths with low levels of emissions require heavy investments in education and knowledge. Northern and Southern growth must be restricted to 1% and 2.8% per year, respectively, over the next 75 years. Politicians who wish to solve the global-warming problem must prepare their polities to accept this reality.\return Key Words: Climate change, sustainability, North-South convergence, international negotiations. JEL Classification: D63, F53, O40, O41, Q50, Q54, Q56.

"Should We Sustain? And if so, Sustain What? Consumption or the Quality of Life?" (2013). Humberto Llavador, John E. Roemer and Joaquim Silvestre. Chapter 30 (pp. 639-665) in R. Fouquet (ed.)  Handbook of Energy and Climate Change, Edward Elgar Publications. Cheltenham, UK, and Northampton, MA, USA. [PDF]

Abstract: The rapid growth in greenhouse gas (GHG) emissions and concomitant increase in atmospheric carbon concentration during the past century have raised, in a dramatic way, the spectre of catastrophic effects for the welfare of mankind: in the last century, the only comparable events were the two world wars and worst-case scenarios associated with nuclear proliferation. Unlike these events, the effects of increased atmospheric carbon concentration, mainly due to associated temperature increases, will occur gradually and with a long time lag. Sustainability has gained traction as an ethic and an appropriate goal, as we face the costs of using up our scarce biospheric resource, of a non-carbon-saturated atmosphere. That ethic is quite pervasive, at least among environmentalists. Perhaps surprisingly, it has influenced economists much less: to wit, the major contributions to the economics of climate change advocate not a ‘sustainabilitarian’ approach, but a utilitarian one, of maximizing the discounted sum of utilities of the sequence of generations beginning with the present one. Indeed, the two most influential pieces of recent economic analysis, William Nordhaus’s (2008) book and Nicholas Stern’s (2007) Review, both employ versions of discounted utilitarianism, as we will examine below.

"Sustainability in the Presence of Global Warming: Theory and Empirics" (2011). Humberto Llavador, John E. Roemer and Joaquim Silvestre. Human Development Research Paper 2011/05. Research commissioned by the UNDP for the Human Development Report 2011. [PDF]

Abstract: Mankind must cooperate to reduce greenhouse gas (GHG) emissions to prevent a catastrophic rise in global temperature, with its concomitant effects on sea level, rainfall, drought, storms, agricultural production, and human migration. What is the appropriate way of evaluating how the costs of reducing GHG emissions should be shared across the present and future generations, and within the next few generations, across regions of the world? How should the intergenerational and inter-regional resource allocation be regulated? These are normative questions: their answers depend upon the theory of distributive justice held. We argue, with respect to the intergenerational question, for a theory of justice that is motivated by the concept of sustainability. With respect to the inter-regional issue, we do not take a fundamentally normative approach, but rather a political approach, where we propose what we believe is a politically acceptable solution to the bargaining problem that is at present taking place between major national actors (think: the US and China) concerning the reductions in GHGs that should be implemented. One reason for the difference in our approaches to these two problems is that future generations cannot bargain with us, and so we should take an ethical posture towards them. Major nations of the world, however, are actively engaged in arguing and bargaining over the second problem, and our role with respect to these negotiations is to behave like an arbitrator and propose what (we believe) is a mutually acceptable solution.

"A Dynamic Analysis of Human Welfare in a Warming Planet" (2011). Humberto Llavador, John E. Roemer and Joaquim Silvestre. Journal of Public Economics 95(11-12):1607-1620. doi:10.1016/j.jpubeco.2011.05.017

Abstract: Climate science indicates that climate stabilization requires low GHG emissions. Is this consistent with nondecreasing human welfare? Our welfare or utility index emphasizes education, knowledge, and the environment. We construct and calibrate a multigenerational model with intertemporal links provided by education, physical capital, knowledge and the environment. We reject discounted utilitarianism and adopt, first, the Pure Sustainability Optimization (or Intergenerational Maximin) criterion, and, second, the Sustainable Growth Optimization criterion, that maximizes the utility of the first generation subject to a given future rate of growth. We apply these criteria to our calibrated model via a novel algorithm inspired by the turnpike property. The computed paths yield levels of utility higher than the level at reference year 2000 for all generations. They require the doubling of the fraction of labor resources devoted to the creation of knowledge relative to the reference level, whereas the fractions of labor allocated to consumption and leisure are similar to the reference ones. On the other hand, higher growth rates require substantial increases in the fraction of labor devoted to education. JEL classification D63;O40;O41;Q50;Q54;Q56 Keywords: Climate change; Education; Maximin; Growth.

"Intergenerational Justice when Future Worlds are Uncertain" (2010). Humberto Llavador, John E. Roemer and Joaquim Silvestre. Journal of Mathematical Economics 46(5):728-761. doi:10.1016/j.jmateco.2010.06.004

Abstract: Let there be a positive (exogenous) probability that, at each date, the human species will disappear. We postulate an Ethical Observer (EO) who maximizes intertemporal welfare under this uncertainty, with expected-utility preferences. Various social welfare criteria entail alternative von Neumann Morgenstern utility functions for the EO: utilitarian, Rawlsian, and an extension of the latter that corrects for the size of population. Our analysis covers, first, a cake-eating economy (without production), where the utilitarian and Rawlsian recommend the same allocation. Second, a productive economy with education and capital, where it turns out that the recommendations of the two EOs are in general different. But when the utilitarian program diverges, then we prove it is optimal for the extended Rawlsian to ignore the uncertainty concerning the possible disappearance of the human species in the future. We conclude by discussing the implications for intergenerational welfare maximization in the presence of global warming. JEL classification: D63; D81; O40; Q54; Q56 Keywords: Discounted utilitarianism; Rawlsian; Sustainability; Maximin; Uncertainty; Expected utility; von Neumann Morgenstern; Dynamic welfare maximization.

Political Economy

"Suffrage Rights" (2017). Humberto Llavador. Oxford Research Encyclopedia. Oxford University Press. doi.org/10.1093/acrefore/9780190228637.012.5

Abstract: The historical evolution of the right to vote offers three observations. First, almost all groups have seen their voting rights challenged at some point in time; and almost all political movements have sought to exclude some other group from voting. Secondly, reforms towards suffrage extension are varied: from the direct introduction of universal (male) suffrage, to a trickle down process of enfranchising a small group at a time. Thirdly, the history of franchise extension is a history of expansions and contractions. Much of the literature on the evolution of the right to vote builds on the following question: why would a ruling elite decide to extend the suffrage to excluded groups who have different interests in the level of redistribution and the provision of public goods? Two competing theories dominate the debate: Bottom-up or demand side theories emphasising the role of revolutionary threats; and top-down or supply side theories, explaining franchise extensions as the outcome of the strategic interactions of those in power and elites in the democratic opposition. A second question addresses the choice of a particular path of franchise extension, asking what explains different strategies and, in particular, the role of their accompanying institutional reforms. In contrast to the literature on the inclusion of the lower classes, women suffrage has been traditionally presented as the conquest of the suffragette movement. Current research, however, departs from this exceptionalism of women suffrage and shows certain consensus in explaining women’s suffrage as a political calculus, in which men willingly extend the franchise when they expect to benefit from it. Arguments differ though in the specific mechanisms that explain the political calculus. Finally, the literature on compulsory voting addresses the estimations of its impact on turnout; whether it translates into more efficient campaigning, improved legitimacy, and better representativity; and ultimately its effects on policies.

"An Agenda-Setting Model of Electoral Competition" (2012). Josep M. Colomer and Humberto Llavador. SERIEs: Journal of the Spanish Economic Association 3(1-2):73-93. doi:10.1007/s13209-011-0056-5

Abstract: This paper presents a model of electoral competition focusing on the formation of the public agenda. An incumbent government and a challenger party in opposition compete in elections by choosing the issues that will key out their campaigns. Giving salience to an issue implies proposing an innovative policy proposal, alternative to the status-quo. Parties trade off the issues with high salience in voters’ concerns and those with broad agreement on some alternative policy proposal. Each party expects a higher probability of victory if the issue it chooses becomes salient in the voters’ decision. But remarkably, the issues which are considered the most important ones by a majority of voters may not be given salience during the electoral campaign. An incumbent government may survive in spite of its bad policy performance if there is no sufficiently broad agreement on a policy alternative. We illustrate the analytical potential of the model with the case of the United States presidential election in 2004. Keywords: Agenda, Elections, Political competition, Issues, Salience, Agreement JEL Classification: D72

"Immigration Policy with Partisan Parties" (2011). Humberto Llavador and Angel Solano. Journal of Public Economics 95(1-2):134-142. doi:10.1016/j.jpubeco.2010.09.011

Abstract: This paper analyzes the political economy of immigration when the salient electoral issue is the level of immigrants and the relevant immigration policy is the expenditure in immigration control. We consider that immigration affects voters' welfare through economic and non-economic factors. We model political competition à la Wittman with the ideology of parties endogenously determined at equilibrium. At equilibrium, parties propose different levels of immigration, located to the left and to the right of the median voter's ideal point, and combine skilled and unskilled workers among their constituencies. Numerical simulations provide the levels of immigration proposed by the two parties and the composition of parties' constituencies as we vary the efficacy of immigration control and the intensity of immigration aversion.

"The Informational Value of Incumbency" (2009). Carmen Beviá and Humberto Llavador. Journal of Public Economic Theory 11(5):775-798. doi:10.1111/j.1467-9779.2009.01429.x 

Abstract: This paper exploits the informational value of incumbency: incumbency confers voters information about governing politicians not available from challengers. We propose a measure of incumbency advantage that improves the use of pure reelection success. We also study the relationship between incumbency advantage, ideological bias, and terms in office. Our argument emphasizes that incumbency affects candidates' chances of winning even if they had no opportunity to strategically utilize policies.

"Why do Parties Exclude Important Issues from their Electoral Campaigns?" (2009). Josep M. Colomer and Humberto Llavador. Chapter 8 in Aragonés, Beviá, Llavador, and Schofield (eds.) The Political Economy of Democracy, Fundació BBVA.

Abstract: This paper discusses the criteria for party choices of issues and the subsequent campaign outcomes, explaining why highly ranked issues in voters’ concern may be left out of the electoral campaign. We present a formal model of electoral competition focusing on the formation of the public agenda, in which political parties or candidates compete to win an election by choosing an issue and a policy position on that issue to which they try to give salience. Giving salience to an issue implies proposing an innovative policy proposal on the issue as an alternative to the status-quo policy, as well as talking about it, usually with a value or argument, and making it news with some effort investment in order to make it relevant for voters’ electoral decisions.

A party will choose a priority issue to campaign for if it is a likely winning issue, that is, it has a likely winning position and it is likely to become decisive in the election. Whether an issue will become a winning issue depends on two variables: (i) the ex-ante ‘pre-campaign salience’ of the issue in voters’ concerns and (ii) the voters’ support or ‘consensus’ in favor of a policy proposal on the issue.

"Voting with Preferences over Margins of Victory" (2008). Humberto Llavador. Mathematical Social Science 56(3):355-365. doi:10.1016/j.mathsocsci.2008.05.009

Abstract: This paper analyzes a two-alternative voting model with the distinctive feature that voters have preferences over margins of victory. We study voting contests with a finite as well as an infinite number of voters, and with and without mandatory voting. The main result of the paper is the existence and characterization of a unique equilibrium outcome in all those situations. At equilibrium, voters who prefer a larger support for one of the alternatives vote for such alternative, providing a formal argument for the conditional sincerity voting condition in [Alesina, Alberto, Rosenthal, Howard, 1995. Partisan Politics, Divided Government, and the Economy. Cambridge University Press, Cambridge] and the benefit of voting function in [Llavador, Humberto, 2006. Electoral platforms, implemented policies and abstention. Social Choice and Welfare 27 (1), 55–81]. Finally, we offer new insights on explaining why some citizens may vote strategically for an alternative different from the one declared as the most preferred. JEL classification: D72 Keywords: Margin of victory; Mandates; Plurality; Abstention; Strategic voting

"Electoral Platforms, Implemented Policies and Abstention" (2006). Humberto Llavador. Social Choice and Welfare 27(1):55-81. doi:10.1007/s00355-006-0111-5

Abstract: This paper distinguishes between electoral platforms and implemented policies through a non-trivial policy-setting process. Voters are sophisticated and may care not only about the implemented policy but also about the platform they support with their vote. We find that while parties tend to polarize their positions, the risk of alienating their constituency prevents them from radicalizing. The analysis evidences that the distribution of the electorate, and not only the (expected) location of a pivotal voter, matters in determining policies. Our results are consistent with the observation of polarized platforms and moderate policies, and the alienation and indifference components of abstention.

"Partisan Competition, Growth and the Franchise" (2005). Humberto Llavador and Robert J. Oxoby. The Quarterly Journal of Economics 120(3):1155-1189. doi:10.1093/qje/120.3.1155

Abstract: We present an argument for changes in the franchise in which an elite split along economic interests uses the suffrage to influence implemented policies. Through the influence of these policies on the character of industrialization, we analyze the effects of franchise changes on economic growth. We identify in the social structure of society an explanation for the connection between enfranchisement and growth: when (1) there exists an economic conflict among the elite, (2) landed classes are not politically strong, and (3) there exists a critical mass of industrial workers, we observe both growth and democratization. The lack of conditions (1) or (2) resolves in stagnant autocracies while the absence of condition (3) drives growth-deterring democratic expansions. We provide historical support for our argument by analyzing the experience of eleven countries.

"Abstention and Political Competition" (2000). Humberto Llavador. Review of Economic Design 5(4):411-1189. doi:10.1007/s100580000030

Abstract: The classical literature on spatial majority voting postulates that all citizens vote. The Median Voter Theorem (MVT) then obtains when parties have perfect information on voter behavior and are either office-seekers (“Downsian”) or ideological. This paper introduces abstention, a simple yet realistic modification. We show that the main features of the MVT survive to a large extent but subject to some qualifications. First, the winning policy does not bear any necessary relation to the median voter. Second, there exist examples in which the candidates choose different positions at equilibrium. Third, equilibrium may fail to exist or be unique. Finally, the equilibria of the model with office-motivated parties may differ from the ones where parties are ideological. JEL classification: D72 Keywords: Abstention, alienation, political competition, median voter theorem.

Welfare Economics

"Nash versus Kant: A game-theoretic analysis of childhood vaccination behavior"
De Donder, Philippe, Humberto Llavador, Stefan Penczynski, John E. Roemer, and Roberto Vélez. Working paper. June 2023 [PDF]

Abstract: The vaccination game exhibits positive externalities. The standard game-theoretic approach assumes that parents make decisions according to the Nash protocol, which is individualistic and non-cooperative. However, in more solidaristic societies, parents may behave cooperatively, optimizing according to the Kantian protocol, in which the equilibrium is efficient. We develop a random utility model of vaccination behavior and prove that the equilibrium coverage rate is larger with the Kant protocol than with the Nash one. Using survey data collected from six countries, we calibrate the parameters of the vaccination game, compute both Nash equilibrium and Kantian equilibrium profiles, and compare them with observed vaccination behavior. We find compelling evidence that parents demonstrate cooperative behavior in all six countries. We argue that the existence of positive externalities has fostered a social norm, leading to higher vaccination rates than predicted by individualistic decision-making, and that the Kantian equilibrium offers one precise version of such social norm. The study highlights the importance of cooperation and social norms in shaping vaccination behavior and underscores the need to consider these factors in public health interventions.

"Inequality, Bipolarization, and Tax Progressivity" (2021). Oriol Carbonell-Nicolau and Humberto Llavador American Economic Journal: Microeconomics 13(4): 492–513. doi: 10.1257/mic.20190111.

Abstract: The case for progressive income taxation is often based on the classic result of Jakobsson (1976) and Fellman (1976), according to which progressive and only progressive income taxes—in the sense of increasing average tax rates on income—ensure a reduction in income inequality. This result has been criticized on the ground that it ignores the possible disincentive effect of taxation on work effort, and the resolution of this critique has been a long-standing problem in public finance. This paper provides a normative rationale for progressivity that takes into account the effect of an income tax on labor supply. It shows that a tax schedule is inequality reducing only if it is progressive—in the sense of increasing marginal tax rates on income, and identifies a necessary and sufficient condition on primitives under which progressive and only progressive taxes are inequality reducing..

​​"Elasticity Determinants of Inequality Reducing Income Taxation" (2021) Oriol Carbonell-Nicolau and Humberto Llavador. Journal of Economic Inequality 19:163-183 doi: 10.1111/0034-6527.00322

Abstract: The link between income inequality and progressive taxation has long been considered a fundamental normative foundation for income tax progressivity. This paper furnishes necessary and sufficient conditions on primitives, in terms of the elasticity of income with respect to ability, under which various subclasses of progressive taxes are inequality reducing. The distributional effects of progressive income taxation are decomposed into two conditions on the wage elasticity of income, the tax rate effect and the subsidy effect, each capturing different aspects of the transition between before-tax and after-tax income distributions. The results confer a degree of useful flexibility to the theory, in that they allow the analyst to expand the universe of consumer preferences by suitably restricting the set of marginal-rate progressive taxes. As an illustration of the results’ practical implications, we provide a precise characterization of the subclass of (progressive) taxes that are inequality reducing for the constant elasticity of substitution (CES) and the quasi-linear utility functions.

"Inequality Reducing Properties of Progressive Income Tax Schedules: The Case of Endogenous Income" (2018). Oriol Carbonell-Nicolau and Humberto Llavador, Theoretical Economics 13(1):39-60. doi:10.3982/TE2533

Abstract: The case for progressive income taxation is often based on the classic result of Jakobsson (1976) and Fellman (1976), according to which progressive and only progressive income taxes—in the sense of increasing average tax rates on income—ensure a reduction in income inequality. This result has been criticized on the ground that it ignores the possible disincentive effect of taxation on work effort, and the resolution of this critique has been a long-standing problem in public finance. This paper provides a normative rationale for progressivity that takes into account the effect of an income tax on labor supply. It shows that a tax schedule is inequality reducing only if it is progressive—in the sense of increasing marginal tax rates on income, and identifies a necessary and sufficient condition on primitives under which progressive and only progressive taxes are inequality reducing..

"An Equal-opportunity Approach to the Allocation of International Aid" (2011). Humberto Llavador and John E. Roemer, Journal of Development Economics 64(1):147-171. doi:10.1016/S0304-3878(00)00128-0.
Reprinted in Kapstein and Rosenthal (eds.) Ethics and International Relations. Chapter 24, pages 495-519. Ashgate Pub Co. 2009.

Abstract: How should international aid be distributed? The most common view is according to some utilitarian formula: in order to maximize the average growth rate of aid recipients or the growth rate of income of the class of recipient countries. Recently, the The World Bank [The World Bank, 1998. Assessing aid, World bank policy research report] has published a study demonstrating the importance of good economic management, within a recipient country, in transforming aid into economic growth. We identify good economic management with effort, and ask, how should aid be distributed to equalize opportunities [among recipient countries] for achieving growth, according to Roemer's theory of equal opportunity [Roemer, J.E., 1998. Equality of Opportunity. Harvard University Press, Cambridge, MA] Keywords: International aid; Equality of opportunity; Utilitarianism JEL classification: D61; D63; O19.

"Mapas de Ayuda para América Latina y el Caribe" (2010). Sergio Tezanos Vázquez and Humberto Llavador. Chapter 7 in Tezano Vázquez (ed.) América Latina y el Caribe - Mapa Estratégico para la Cooperación, . Editorial Civitas.

Abstract: How should international aid be distributed? The most common view is according to some utilitarian formula: in order to maximize the average growth rate of aid recipients or the growth rate of income of the class of recipient countries. Recently, the The World Bank [The World Bank, 1998. Assessing aid, World bank policy research report] has published a study demonstrating the importance of good economic management, within a recipient country, in transforming aid into economic growth. We identify good economic management with effort, and ask, how should aid be distributed to equalize opportunities [among recipient countries] for achieving growth, according to Roemer's theory of equal opportunity [Roemer, J.E., 1998. Equality of Opportunity. Harvard University Press, Cambridge, MA] Keywords: International aid; Equality of opportunity; Utilitarianism JEL classification: D61; D63; O19.

Other

"Teaching Microeconomic Principles with Smartphones -Lessons from classroom experiments with classEx" (2017). Marcus Giamattei and Humberto Llavador. Barcelona School of Economics Working Paper 996

Abstract: The case for progressive income taxation is often based on the classic result of Jakobsson (1976) and Fellman (1976), according to which progressive and only progressive income taxes—in the sense of increasing average tax rates on income—ensure a reduction in income inequality. This result has been criticized on the ground that it ignores the possible disincentive effect of taxation on work effort, and the resolution of this critique has been a long-standing problem in public finance. This paper provides a normative rationale for progressivity that takes into account the effect of an income tax on labor supply. It shows that a tax schedule is inequality reducing only if it is progressive—in the sense of increasing marginal tax rates on income, and identifies a necessary and sufficient condition on primitives under which progressive and only progressive taxes are inequality reducing.

 "Experiments in Political Economy" (2016) Humberto Llavador and Robert Oxoby. Chapter 8 in Brañas-Garza, A. and A. Cabrales (eds.) Experimental Economics. Volume II: Economic Applications, pages 166-181. Palgrave-McMillan.

"Experimentos en Economía Política" (2011). Humberto Llavador and Robert Oxoby. Chapter 17 in Brañas-Garza, A (ed.)  Economía Experimental y del Comportamiento. Editorial Antoni Bosch.