Documents de travail

Résumé The relationship between public debt, growth and volatility is investigated in a Barro-type (1990) endogenous growth model, with three main features: we consider a small open economy, international borrowing is constrained and households have taste for domestic public debt. Therefore, capital, public debt and the international asset are not perfect substitutes and the economy is characterized by an investment multiplier. Whatever the level of the debt-output ratio, the existing BGP features expectation-driven fluctuations. If the debt-output ratio is low enough, there is also a second BGP with a lower growth rate. Hence, lower debt does not stabilize the economy with credit market imperfections. However, a high enough taste for domestic public debt may rule out the BGP with lower growth. This means that if the share of public debt hold by domestic households is high enough, global indeterminacy does not occur.
Mots clés Small open economy, Public debt, Credit constraint, Indeterminacy
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Résumé Tests are crucial to know about the number of people who have fallen ill with COVID-19 and to understand in real-time whether the dynamics of the pandemic is accelerating or decelerating. But tests are a scarce resource in many countries. The key but still open question is thus how to allocate tests across sub-national levels. We provide a data-driven and operational criterion to allocate tests efficiently across regions or provinces, with the view to maximize detection of people who have been infected. We apply our criterion to Italian regions and compute the shares of tests that should go to each region, which are shown to differ significantly from the actual distribution.
Mots clés COVID-19, Italy, Acceleration of harm, Deceleration of harm, Epidemic dynamics, Efficiency criterion, Sub-national allocation of tests, Real-time Analysis
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Résumé Tests are crucial to know about the number of people who have fallen ill with COVID-19 and to understand in real-time whether the dynamics of the pandemic is accelerating or decelerating. But tests are a scarce resource in many countries. The key but still open question is thus how to allocate tests across sub-national levels. We provide a data-driven and operational criterion to allocate tests efficiently across regions or provinces, with the view to maximize detection of people who have been infected. We apply our criterion to Italian regions and compute the shares of tests that should go to each region, which are shown to differ significantly from the actual distribution.
Mots clés Sub-national allocation of tests, Real-time Analysis, COVID-19, Epidemic dynamics, Acceleration of harm, Deceleration of harm, Italy, Efficiency criterion
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Résumé Several recent papers introduce different mechanisms to explain why asset bubbles are observed in periods of larger growth. These papers share common assumptions, heterogeneity among traders and credit market imperfection , but differ in the role of the bubble, used to provide liquidities or as collateral in a borrowing constraint. In this paper, we introduce heterogeneous traders by considering an overlapping generations model with households living three periods. Young households cannot invest in capital, while adults have access to investment and face a borrowing constraint. Introducing bubbles in a quite general way, encompassing the different roles they have in the existing literature, we show that the bubble may enhance growth when the borrowing constraint is binding. More significantly, our results do not depend on the-liquidity or collateral-role attributed to the bubble. We finally extend our analysis to a stochas-tic bubble, which may burst with a positive probability. Because credit and bubble are no more perfectly substitutable assets, the liquidity and collateral roles of the bubble are not equivalent. Growth is larger when bubbles play the liquidity role, because the burst of a bubble used for liquidity is less damaging to agents who invest in capital.
Mots clés Growth, Crowding-in effect, Collateral, Bubble, Liquidity
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Résumé Several recent papers introduce different mechanisms to explain why asset bubbles are observed in periods of larger growth. These papers share common assumptions, heterogeneity among traders and credit market imperfection , but differ in the role of the bubble, used to provide liquidities or as collateral in a borrowing constraint. In this paper, we introduce heterogeneous traders by considering an overlapping generations model with households living three periods. Young households cannot invest in capital, while adults have access to investment and face a borrowing constraint. Introducing bubbles in a quite general way, encompassing the different roles they have in the existing literature, we show that the bubble may enhance growth when the borrowing constraint is binding. More significantly, our results do not depend on the-liquidity or collateral-role attributed to the bubble. We finally extend our analysis to a stochas-tic bubble, which may burst with a positive probability. Because credit and bubble are no more perfectly substitutable assets, the liquidity and collateral roles of the bubble are not equivalent. Growth is larger when bubbles play the liquidity role, because the burst of a bubble used for liquidity is less damaging to agents who invest in capital.
Mots clés Liquidity, Bubble, Collateral, Crowding-in effect, Growth
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Résumé The radical uncertainty around the current COVID19 pandemics requires that governments around the world should be able to track in real time not only how the virus spreads but, most importantly, what policies are effective in keeping the spread of the disease under check. To improve the quality of health decision-making, we argue that it is necessary to monitor and compare acceleration/deceleration of confirmed cases over health policy responses, across countries. To do so, we provide a simple mathematical tool to estimate the convexity/concavity of trends in epidemiological surveillance data. Had it been applied at the onset of the crisis, it would have offered more opportunities to measure the impact of the policies undertaken in different Asian countries, and to allow European and North-American governments to draw quicker lessons from these Asian experiences when making policy decisions. Our tool can be especially useful as the epidemic is currently extending to lower-income African and South American countries, some of which have weaker health systems.
Mots clés Acceleration, Convexity, COVID-19, Data Dashboard, Detection of Infectious Diseases, Public Health Policy, Sensitivity
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Résumé We study intergenerational wealth mobility and its evolution in France over the period 1960-2015. More precisely, we identify the persistence of homeownership between parents and children as indicator of wealth mobility in France. We also provide evidence about different sources of heterogeneity in intergenerational homeownership associations in terms of education and geographic areas. Finally, we study the main transmission mechanism: direct financial transfers. We use all available French wealth surveys since 1986 and perform a data panelization using retrospective information. We document multiple results. First, intergenerational correlation in homeownership status has dramatically increased, particularly since the 1990s. Second, this rise is concentrated among people aged between 20 and 39 years old. Third, we observe higher wealth persistence at the top. Four, we find a strong significant effect of direct wealth transfers on the probability of becoming homeowner, which lasts 5 years. Moreover, parental support is substantially more important for households with no diploma, suggesting a crucial role of human capital on wealth formation. Finally, this phenomenon is intensified in areas with high urban concentration; highlighting the potential role of house prices as determinant of wealth social determinism.
Mots clés Wealth transmission, Housing, Homeownership, Intergenerational Mobility
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Résumé This paper provides a tool to build climate change scenarios to forecast Gross Domestic Product (GDP), modelling both GDP damage due to climate change and the GDP impact of mitigating measures. It adopts a supply-side, long-term view, with 2060 and 2100 horizons. It is a global projection tool (30 countries / regions), with assumptions and results both at the world and the country / regional level. Five different types of energy inputs are taken into account according to their CO2 emission factors. Full calibration is possible at each stage, with estimated or literature-based default parameters. In particular, Total Factor Productivity (TFP), which is a major source of uncertainty on future growth and hence on CO2 emissions, is endogenously determined, with a rich modeling encompassing energy prices, investment prices, education, structural reforms and decreasing return to the employment rate. We present four scenarios: Business As Usual (BAU), with stable energy prices relative to GDP price; Decrease of Renewable Energy relative Price (DREP), with the relative price of non CO2 emitting electricity decreasing by 2% a year; Low Carbon Tax (LCT) scenario with CO2 emitting energy relative prices increasing by 1% per year; High Carbon Tax (HCT) scenario with CO2 emitting energy relative prices increasing by 3% per year. At the 2100 horizon, global GDP incurs a loss of 12% in the BAU, 10% in the DREP, 8% in the Low Carbon Tax scenario and 7% in the High Carbon Tax scenario. This scenario exercise illustrates both the "tragedy of the horizon", as gains from avoided climate change damage net of damage from mitigating policies are negative in the medium-term and positive in the long-term, and the "tragedy of the commons", as climate change damage is widely dispersed and particularly severe in developing economies, while mitigating policies should be implemented in all countries, especially in advanced countries modestly affected by climate change but with large CO2 emission contributions.
Mots clés Energy prices, Climate, Global warming, Long- term projections, Productivity, Growth, Government policy
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Résumé Although it is widely acknowledged that non-cognitive skills matter for adult outcomes, little is known about the role played by family environment in the formation of these skills. We use a longitudinal survey of children born in the UK in 2000-2001, the Millennium Cohort Study by the Centre for Longitudinal Studies, to estimate the effect of family size on socio-emotional skills, measured by the Strengths and Difficulties Questionnaire. To account for the endogeneity of fertility decisions, we use a well-known instrumental approach that exploits parents' preference for children's gender diversity. We show that the birth of a third child negatively affects the socio-emotional skills of the first two children in a persistent manner. However, we show that this negative effect is entirely driven by girls. We provide evidence that this gender effect is partly driven by an unequal response of parents' time investment in favour of boys and, to a lesser extent, by an unequal demand for household chores.
Mots clés Child development, Birth order, Family size, Non-cognitive skills
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Résumé How to allocate limited resources among children is a crucial household decision, especially in developing countries where it might have strong implications for children and family survival. We provide the first systematic study linking variations in parental income in the early life of children to subsequent child health and parental investments across siblings in developing countries, using data from multiple waves of the Demographic and Health Surveys spanning 54 countries. Variations in the world prices of locally produced crops are used as measures of local income. We find that children born in periods of higher income receive better human capital (health and education) investments and durably enjoy better health than their siblings. Children whose siblings were born during favourable income periods receive less investment and exhibit worse health. We also provide evidence that other investments (education, fertility) react to sibling rivalry, and show that these within-households adjustments matter at the aggregate level.
Mots clés Health, Income, Parental investments, Intra-household allocations
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