Working papers
Data on EU economies show no correlation between low-skilled immigration and the skill premium. We rationalise this evidence in a model where firms face search and screening costs. Low-skilled immigration diminishes the relative benefit of screening skilled workers, leading to a decline in their relative ability within the firm and an undetermined impact on the skill premium. On region-sector and firm level data from 2008 to 2013, we find that low-skilled immigration in Italian regions has reduced skill intensity without affecting the skill premium. Using proxies for workers’ ability and screening activity, we provide supporting evidence for the theorised mechanisms.
wp_2024_-_nr_14.pdf (1.43 MB) In this paper, we bring fresh evidence on the city size distribution from a ‘lab’ represented by the region of Bukhara observed in the 9th CE. At that time this region was homogeneous in all respects (technology, amenities, climate, culture, language, religion, etc.) and yet cities had different sizes. We rationalize the city size distribution of this economy in a simple general equilibrium spatial model of which we estimate the parameters using the method of moments. The estimated model predicts very well the 9th century city size distribution. Spatial centrality is the major determinant of city size. The silk road contributes to explain what centrality cannot. We find little evidence of persistence of the urban structure when comparing the 9th and the 21st century. We find instead that centroid of the region has moved towards the economic core of the Uzbek economy.
wp_2024_-_nr_13.pdf (14.91 MB) The strongest empirical regularity about the exchange rate pass-through is that it is incomplete. We provide a new theoretical explanation based on the unwillingness of some firms to price discriminate between markets. These firms set a single price to all destinations and adjust it when the exchange rate shock occurs. But the adjustment is not necessarily proportional since the change in the single price affects revenues in all markets. The single price strategy also implies a “pass-around” effect: The exchange rate shock has repercussions of price changes to all export markets. The analysis of price changes operated by French exporters in different markets after the EUR/CHF shock of 2015 provides evidence in favour of our theoretical explanation.
wp_2024_-_nr_12.pdf (724.81 KB) Across countries, women and men allocate time differently between market work, domestic services, and care work. In this paper, we document the gender division of work,
drawing on a new harmonized data set that provides us with high-quality time use data for 50 countries spanning the global income distribution. A striking feature of the data is the wide dispersion across countries at similar income levels. We use these data to motivate a macroeconomic model of household time use in which country-level allocations are shaped by wages and a set of “wedges” that resemble productivity, preferences, and disutilities. Taking the model to country-level observations, we find that a wedge related to the disutility of market work for women plays a crucial role in generating the observed dispersion of outcomes, particularly for middle-income countries. Variation in the division of non-market work is principally shaped by a wedge indicating greater disutility for men, which is especially large in some low- and middle-income countries.
wp_2024_-_nr_11.pdf (10.38 MB) Dynasties constitute a visible sign of intergenerational persistence and raise questions about the legitimacy of the ruling elite. This paper uses data on graduates of elite colleges to explore the influence of political and business dynasties in France. I link nominative data on 103,309 graduates of 12 French Grandes ´ Ecoles born between 1931 and 1975 to their professional careers as politicians with national-level mandates or as board members of French firms. Identifying lineage through surnames, I find that sons of political and business leaders were substantially more likely than their graduate peers to pursue elite careers themselves, revealing a social gradient in returns to elite education. Political dynasties were particularly sizeable, although progressively declining. These dynasties also affected the composition of the French elite: fewer dynastical board members were graduates of top colleges than their first-generation colleagues. Yet, they were propelled much younger into top business and political positions.
wp_2024_-_nr_10.pdf (869.98 KB) The Airplane Carbon Barter (ACB) mechanism is a sort of Personal Carbon Trading (PCT) system for allocating emissions allowances to French air travelers, combined with a barter mechanism at the shadow carbon price of €100 in the first year, and following the price growth trajectory defined in the Quinet II report for the following years. Based on the latest available data, each French citizen would have an emission allowance of 0.4 tons of carbon in the first year. The modus operandi is similar to a Covid-type app, with a QR code required at check-in by airlines to obtain a boarding pass. The personal carbon account is reserved for French nationals or residents of France. We estimate that the TCA could lead to a 6% reduction in total emissions in the first year, for a market exchange value of around €1.5 billion. The TCA is also a transfer mechanism that redistributes purchasing power essentially from the last decile to the first decile, which could increase its purchasing power by 0.5%. We also propose a variant of the ACB mechanism to make it consistent with the EU-ETS.
wp_2024_-_nr_09.pdf (1.03 MB) In this paper, we provide a simple framework to show the existence of stationary bubbles on dividend-yielding financial assets. These bubbles are compatible with a positive stationary fundamental value, rather than requiring its collapse in the long run. This result is obtained in an exchange overlapping generations economy with vintage financial assets that depreciate over time. New assets are introduced in each period, ensuring a constant aggregate supply of financial assets. Depreciation introduces a gap between the return of bubbles and the rate at which the dividends are discounted. Because the return of bubble can be lower or equal to the growth rate, we can have stationary equilibria with both a positive bubble and a positive fundamental value. Finally, our framework also allows us to discuss the role of the substitutability between financial assets on the level of bubbles and fundamental values.
wp_2024_-_nr_08.pdf (608.1 KB) 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.
wp_2024_-_nr_07.pdf (971.59 KB) We present an overview of selected contributions of the Journal of Mathematical Economics' authors in the last half century. We start with the classical optimal growth theory within a benchmark multisector model and outline the successive developments in the analysis of this model, including the turnpike theory. Different refinements of the benchmark are considered along the way. We after survey the abundant literature on endogenous fluctuations in two-sector models. We conclude with two strong trends in the recent growth literature: green growth and infinite-dimensional growth models.
wp_2024_-_nr_06.pdf (563.29 KB) This paper derives closed-form solutions for a strategic, simultaneous harvesting in a predator-prey system. Using a parametric constraint, it establishes the existence and uniqueness of a linear feedback-Nash equilibrium involving two specialized fleets and allow for continuous time results for a class of payoffs that have constant elasticity of the marginal utility. Theses results contribute to the scarce literature on analytically tractable predator-prey models with endogenous harvesting. A discussion based on industry size effects is provided to highlight the role played by biological versus strategic interactions in the multi-species context.
wp_2024_-_nr_05.pdf (2.12 MB) The assessment of binary classifier performance traditionally centers on discriminative ability using metrics, such as accuracy. However, these metrics often disregard the model’s inherent uncertainty, especially when dealing with sensitive decision-making domains, such as finance or healthcare. Given that model-predicted scores are commonly seen as event probabilities, calibration is crucial for accurate interpretation. In our study, we analyze the sensitivity of various calibration measures to score distortions and introduce a refined metric, the Local Calibration Score. Comparing recalibration methods, we advocate for local regressions, emphasizing their dual role as effective recalibration tools and facilitators of smoother visualizations. We apply these findings in a real-world scenario using Random Forest classifier and regressor to predict credit default while simultaneously measuring calibration during performance optimization.
wp_2024_-_nr_04.pdf (3.04 MB) Can forced sterilization programs targeting men lead to male-perpetrated violence? This paper investigates the impact of a government-mandated male sterilization program introduced in India on the rise of violence. Launched in April 1976, the program predominantly targeted men and saw heterogeneous implementation across India over 10 months. Using various household surveys and newly digitized historical data sources, we study whether the program triggered unintended effects on violence, measured by crime rates. Using a difference-indifferences strategy by exploiting geographical variation in coercion intensity, we find that an increase in exposure to the program led to an increase in violent crime rates of 7% for the average district, which persisted over time. Violent crimes against women primarily drive the increase in crime rates, as rapes are increasing by 22% for the average district. We find that the program was ineffective in reducing fertility, so we hypothesize that a forced sterilization program targeting men may increase violence against women through two main channels: the program inducing trauma and impacting perceptions of masculinity. In line with those channels, we see that districts with high coercion intensity correlate with more harmful gender norms: higher levels and acceptance of Intimate Partner Violence, lower bargaining power of women and lower contraception adoption.
wp_2024_-_nr_03.pdf (2.08 MB) This paper investigates the dynamic effects of weather shocks on monthly agricultural production in Peru, using a Local Projection framework. An adverse weather shock, measured by an excess of heat or rain, always generates a delayed negative downturn in agricultural production, but its magnitude and duration depend on several factors, such as the type of crop concerned or the timing at which it occurs. On average, a weather shock –a temperature shock– can cause a monthly decline of 5% in agricultural production for up to four consecutive months. The response is time-dependent: shocks occurring during the growing season exhibit a much larger response. At the macroeconomic level, weather shocks are recessionary and entail a decline in inflation, agricultural production, exports, exchange rate and GDP.
wp_2024_-_nr_02.pdf (1.95 MB) This paper shows how to recover behavioral biases from revealed preference ranking implied by choices. The approach formalizes and unifies well-known behavioral models, including salience thinking, inattention, and logarithmic perception, thereby accounting for many well-documented choice puzzles. I show that this approach provides a way to filter out choice data from behavioral biases explaining rationality breaches before fitting parametric utility models. The approach is applied to workhorse data sets of the literature on choice under risk and scanner consumer choices.
wp_2024_-_nr_01.pdf (685.55 KB) 
