AMU - AMSE
5-9 Boulevard Maurice Bourdet, CS 50498
13205 Marseille Cedex 1
Melindi-Ghidi
Publications
This paper develops an overlapping generations model that links a public health system to a pay-as-you-go (PAYG) pension system. It relies on two assumptions. First, the health system directly finances curative health spending on the elderly. Second, public pensions partially depend on health status by introducing a component indexed to society’s average level of old-age disability. Reducing the average disability rate in the economy then lowers pension benefits as the need to finance long-term care services also drops. We study the effects of introducing such a ‘comprehensive’ Social Security system on individual decisions, capital accumulation, and welfare. We first show that health investments can boost savings and capital accumulation under certain conditions. Second, if individuals are sufficiently concerned with their health when old, it is optimal to introduce a health-dependent pension system, as this will raise social welfare compared to a system where pensions are not tied to the society’s average level of old-age disability. Our analysis thus highlights an important policy recommendation: making PAYG pension schemes partially health-dependent can be beneficial to society.
What is the role of income polarization for explaining differentials in public funding of education? To answer this question, we provide a new theoretical modelling for the income distribution that can directly monitor income polarization. It leads to a new income polarization index where the middle class is represented by an interval. We implement this distribution in a political economy model with endogenous fertility and public/private educational choices. We show that when households vote on public schooling expenditures, polarization matters for explaining disparities in public education funding across communities. Using micro-data covering two groups of school districts, we find that both income polarization and income inequality affect public school funding with opposite signs whether there exist a Tax Limitation Expenditure (TLE) or not.
In this paper, we study the gains and losses incurred during the COVID-19 pandemic. We distinguish between the effects of the pandemic and those of the health measures implemented to reduce the death toll, notably “the lockdown.” Our theoretical model is focused on within-sector firm heterogeneity and involves imperfect competition in a partial equilibrium setting. A comparison between the gains and losses triggered by both the pandemic and the lockdown indicates that an excess profits tax imposed on the “winners” could partly compensate the “losers” of the same sector.
This paper examines the adaptation policy of Small Island Developing States (SIDS) facing climate change. We consider a dynamic economy with the following ingredients: (i) natural capital is an input in local production that is degraded as a result of climate change; (ii) the government has two instruments to cope with climate-related damages: it can adjust the population size thanks to migration policies and/or it can undertake adaptation measures in order to slow the degradation of natural assets; (iii) expatriates send remittances back home. We identify two critical conditions on the fundamentals of the economy that helps understand the features of the optimal policy. We especially show that in most situations, the migration policy is a valuable instrument. Calibrating the model for Caribbean SIDS, we find that the optimal policy of the Caribbean region displays heterogeneity, that is explained by the different degradation rate, population size, and endowment in natural capital. We also highlight that the higher the climate damages, the higher the incentives to conduct an active adaptation policy, combining conventional adaptation actions and migration.
Elite-biased democracies are those democracies in which former political incumbents and their allies coordinate to impose part of the autocratic institutional rules in the new political regime. We document that this type of democratic transition is much more prevalent than the emergence of pure (popular) democracies in which the majority decides the new institutional rules. We then develop a theoretical model explaining how an elite-biased democracy may arise in an initially autocratic country. To this end, we extend the benchmark political transition model of Acemoglu and Robinson (2005) along two essential directions. First, population is split into majority versus minority groups under the initial autocratic regime. Second, the minority is an insider as it benefits from a more favourable redistribution by the autocrat. We derive conditions under which elite-biased democracies emerge and characterise them, in particular with respect to pure democracies.
Intermediary organisations have increasingly played a role in payments for agri-environment services across Europe over the last two decades. However, the economics literature has so far not examined the impact of this new governance mechanism on environmental protection and on individuals' behaviour. We develop a new theoretical economic framework to compare an incentive mechanism using intermediaries, such as environmental knowledge brokers and information providers, with a standard central governance mechanism, in terms of environmental impact. We show that the emergence of knowledge intermediaries is particularly effective where farmers initially have low environmental awareness, or when the public institution organising the scheme is insufficiently aware of individuals' characteristics. Our findings provide theoretical support for previous empirical results on payment schemes for agri-environment measures.
As illustrated by some French departments, how can we explain the existence of equilibria with different fertility and growth rates in economies with the same fundamentals, preferences, technologies and initial conditions? To answer this question we develop an endogenous growth model with altruism and love for children. We show that independently from the type of altruism, a multiplicity of equilibria might emerge if the degree of love for children is high enough. We refer to this condition as the love for children hypothesis. Then, the fertility rate is determined by expectations on the future growth rate and the dynamics are not path-dependent. Our model is able to reproduce different fertility behaviours in a context of completed demographic transition independently from fundamentals, preferences, technologies and initial conditions.
Why, in some urban communities, do rich and poor households cohabit while, in others, we observe sorting by income? Does income inequality impact residential choices and community segregation? To answer these questions, I develop a two-community general equilibrium framework of school quality, residential choice, and tax decision with probabilistic voting. The model predicts that an equilibrium with income mixing in which households segregate across public schools and low- and high-income households choose to live in the same community might emerge in highly unequal societies. In this particular equilibrium, income-mixing communities perform lower public school quality than communities populated by middle-income households. The effect of inequality on the quality of public schooling in the income-mixing community is ambiguous and depends on the relative endowments of private goods, such as housing, in the two communities.
In this paper, we study the production and dissemination of public knowledge goods, such as technological knowledge, generated by a network of voluntarily cooperating innovators. We develop a private-collective model of public knowledge production in networked innovation systems, where group-based social preferences have an impact on the coalition formation of developers. Our model builds on the large empirical literature on voluntary production of pooled public knowledge goods, including source code in communities of software developers or data provided to open access data repositories. Our analysis shows under which conditions social preferences, such as ‘group belonging’ or ‘peer approval’, influence the stable coalition size, as such rationalising several stylized facts emerging from large-scale surveys of open-source software developers, previously unaccounted for. Furthermore, heterogeneity of social preferences is added to the model to study the formation of stable but mixed coalitions.
This paper analyses the possibility of building a mutually supportive dynamics between internally and externally motivated behaviour for biodiversity conservation and ecosystem services provision. To this purpose a face to face survey amongst 169 key actors of 34 highly successful and prominent biodiversity arrangements in seven EU countries was conducted. The main finding of the paper is the feasibility of combining inherently intrinsically motivated behaviours (providing enjoyment, pleasure from experimentation and learning, aesthetic satisfaction) and internalized extrinsic motivations (related to the identification with the collective goals of conservation policy) through a common set of governance features. Successful initiatives that combine internal and external motivations share the following features: inclusive decision making processes, a broad monitoring by “peers” beyond the core staff of the initiatives, and a context that is supportive for the building of autonomous actor competences. These findings are in line with the psycho-sociological theory of motivation, which shows the importance of a psycho-social context leading to a subjective perception of autonomy and a sense of competence of the actors.