Publications

A Pedagogical Note on Risk Sharing Versus Instability in International Financial Integration: When Obstfeld Meets StiglitzRaouf Boucekkine et Benteng Zou, Open Economies Review, Volume 30, Issue 1, pp. 179-190, 2019

The pure risk sharing mechanism implies that financial liberalization is growth enhancing for all countries as the world portfolio shifts from safe low-yield capital to riskier high-yield capital. This result is typically obtained under the assumption that the volatilities for risky assets prevailing under autarky are not altered after liberalization. We relax this assumption within a simple two-country model of intertemporal portfolio choices. By doing so, we put together the risk sharing effect and a well-defined instability effect. We identify the conditions under which liberalization may cause a drop in growth. These conditions combine the typical threshold conditions outlined in the literature, which concern the deep characteristics of the economies, and size conditions on the instability effect induced by liberalization.

Stability in games with continua of equilibriaSebastian Bervoets et Mathieu Faure, Journal of Economic Theory, Volume 179, pp. 131-162, 2019

The stability of Nash equilibria has often been studied by examining the asymptotic behavior of the best-response dynamics. This is generally done in games where interactions are global and equilibria are isolated. In this paper, we analyze stability in contexts where interactions are local and where there are continua of equilibria. We focus on the public good game played on a network, where the set of equilibria is known to depend on the network structure (Bramoullé and Kranton, 2007), and where, as we show, continua of equilibria often appear. We provide necessary and sufficient conditions for a component of Nash equilibria to be asymptotically stable vis-à-vis the best-response dynamics. Interestingly, we demonstrate that these conditions relate to the structure of the network in a simple way. We also provide corresponding results for several dynamical systems related to the best response.

On the interplay between speculative bubbles and productive investmentXavier Raurich et Thomas Seegmuller, European Economic Review, Volume 111, pp. 400-420, 2019

The aim of this paper is to study the interplay between long term productive investments and more short term and liquid speculative ones. A three-period lived overlapping generations model allows us to make this distinction. Agents have a portfolio decision. When young, they can invest in human capital that is a productive long term investment that provides a return during the following two periods. When young or in the middle age, they can invest in a bubble. Young individuals can also borrow on a credit market to finance the productive investment. However, the amount borrowed is limited by a credit constraint. We show that the existence of a stationary bubble raises productive investment and production when the bubleless economy is credit constrained and dynamically efficient. Indeed, young agents sell short the bubble to increase productive investments, whereas traders at middle age transfer wealth to old age. The bubble allows to relax the credit constraint. We outline that a permanent technological shock inducing either a larger return of capital in the short term or a similar increase in the return of capital in both periods raises productive capital, production and the bubble size. We use our framework to discuss the effect on the occurrence of bubbles of financial regulation and fiscal policy.

Crisis at home: mancession-induced change in intrahousehold distributionOlivier Bargain et Laurine Martinoty, Journal of Population Economics, Volume 32, Issue 1, pp. 277-308, 2019

The Great Recessions was essentially a “mancession” in countries like Spain, the UK, or the USA, i.e., it hist men harder than women for they were disproportionately represented in heavily affected sectors. We investigate how the mancession, and more generally women’s relative opportunities on the labor market, translates into within-household redistribution. Precisely, we estimate the spouses’ resource shares in a collective model of consumption, using Spanish data over 2006–2011. We exploit the gender-oriented evolution of the economic environment to test two original distribution factors: first the regional-time variation in spouses’ relative unemployment risks, and then the gender-differentiated shock in the construction sector (having a construction sector husband after the outburst of the crisis). Both approaches conclude that the resource share accruing to Spanish wives increased by around 7–9% on average, following the improvement of their relative labor market positions. Among childless couples, we document a 5–11% decline in individual consumption inequality following the crisis, which is essentially due to intrahousehold redistribution.

The Patient-Reported Experience Measure for Improving qUality of care in Mental health (PREMIUM) project in France: study protocol for the development and implementation strategySara Fernandes, Guillaume Fond, Xavier Zendjidjian, Pierre Michel, Karine Baumstarck, Christophe Lançon, Fabrice Berna, Franck Schurhoff, Bruno Aouizerate, Chantal Henry, et al., Patient Preference and Adherence, Volume 13, pp. 165-177, 2019

Background:
Measuring the quality and performance of health care is a major challenge in improving the efficiency of a health system. Patient experience is one important measure of the quality of health care, and the use of patient-reported experience measures (PREMs) is recommended. The aims of this project are 1) to develop item banks of PREMs that assess the quality of health care for adult patients with psychiatric disorders (schizophrenia, bipolar disorder, and depression) and to validate computerized adaptive testing (CAT) to support the routine use of PREMs; and 2) to analyze the implementation and acceptability of the CAT among patients, professionals, and health authorities.

Methods:
This multicenter and cross-sectional study is based on a mixed method approach, integrating qualitative and quantitative methodologies in two main phases: 1) item bank and CAT development based on a standardized procedure, including conceptual work and definition of the domain mapping, item selection, calibration of the item bank and CAT simulations to elaborate the administration algorithm, and CAT validation; and 2) a qualitative study exploring the implementation and acceptability of the CAT among patients, professionals, and health authorities.

Discussion:
The development of a set of PREMs on quality of care in mental health that overcomes the limitations of previous works (ie, allowing national comparisons regardless of the characteristics of patients and care and based on modern testing using item banks and CAT) could help health care professionals and health system policymakers to identify strategies to improve the quality and efficiency of mental health care.

The economic returns of ending the AIDS epidemic as a public health threatErik Lamontagne, Mead Over et John Stover, Health Policy, Volume 123, Issue 1, pp. 104-108, 2019

BACKGROUND:
In 2016, countries agreed on a Fast-Track strategy to "end the AIDS epidemic by 2030". The treatment and prevention components of the Fast-Track strategy aim to markedly reduce new HIV infections, AIDS-related deaths and HIV-related discrimination. This study assesses the economic returns of this ambitious strategy.

METHODS:
We estimated the incremental costs, benefits and economic returns of the Fast-Track scenario in low- and middle-income countries, compared to a counterfactual defined as maintaining coverage of HIV-related services at 2015 levels. The benefits are calculated using the full-income approach, which values both the changes in income and in mortality, and the productivity approach.

FINDINGS:
The incremental costs of the Fast-Track scenario over the constant scenario for 2017-2030 represent US$86 billion or US$13.69 per capita. The full-income valuation of the incremental benefits of the decrease in mortality amounts to US$88.14 per capita, representing 6.44 times the resources invested for all countries. These returns on investment vary by region, with the largest return in the Asia-Pacific region, followed by Eastern and Southern Africa. Returns using the productivity approach are smaller but ranked similarly across regions.

INTERPRETATION:
In all regions, the economic and social value of the additional life-years saved by the Fast-Track approach exceeds its incremental costs, implying that this strategy for ending the AIDS epidemic is a sound economic investment.

Coase Lecture ‐ The Inverted‐U Relationship Between Credit Access and Productivity GrowthPhilippe Aghion, Antonin Bergeaud, Gilbert Cette, Rémy Lecat et Hélène Maghin, Economica, Volume 86, Issue 341, pp. 1-31, 2019

We identify two counteracting effects of credit access on productivity growth: on the one hand, better access to credit makes it easier for entrepreneurs to innovate; on the other hand, better credit access allows less efficient incumbent firms to remain longer on the market, thereby discouraging entry of new and potentially more efficient innovators. We first develop a simple model of firm dynamics and innovation‐based growth with credit constraints, where the above two counteracting effects generate an inverted‐U relationship between credit access and productivity growth. Then we test our theory on a comprehensive French manufacturing firm‐level dataset. We first show evidence of an inverted‐U relationship between credit constraints and productivity growth when we aggregate our data at the sectoral level. We then move to firm‐level analysis, and show that incumbent firms with easier access to credit experience higher productivity growth, but that they also experience lower exit rates, particularly the least productive firms among them. To support these findings, we exploit the 2012 Eurosystem's Additional Credit Claims programme as a quasi‐experiment that generated an exogenous extra supply of credits for a subset of incumbent firms.

Managing competition on a two-sided platformPaul Belleflamme et Martin Peitz, Journal of Economics & Management Strategy, Volume 28, Issue 1, pp. 5-22, 2019

On many two-sided platforms, users on one side not only care about user participation and usage levels on the other side, but they also care about participation and usage of fellow users on the same side. Most prominent is the degree of seller competition on a platform catering to buyers and sellers. In this paper, we address how seller competition affects platform pricing, product variety, and the number of platforms that carry trade.