Causality in the Social Sciences: a structural modelling framework

Quality & Quantity - There is no unified theory of causality in the sciences and in philosophy. In this paper, we focus on a particular framework, called structural causal modelling (SCM), as...     

A preliminary comparison of the retail level effects of genetically modified food labelling policies in Canada and France

Most developed countries have adopted labelling policies for genetically modified (GM) food. In April 2004, Canada implemented a voluntary labelling policy for GM and non-GM food, while France adopted the European Union’s new extended mandatory labelling of GM food. I present the result of a qualitative survey of GM and non-GM food labels in supermarkets in Canada and France, five months after the introduction of the new policies. I find that there are almost no GM labelled products in France and non-GM labelled products in Canada. Each policy tends to crowd out the targeted label attribute. However, Canadian consumers can choose between GM and non-GM organic products, whereas there are only non-GM products in French supermarkets. Recent political developments in Quebec suggest that the labelling landscape may change in Canada, either with an increase in the number of non-GM products at the retail level or a transition towards a mandatory labelling policy like in France.     

Inference in models with adaptive learning

Identification of structural parameters in models with adaptive learning can be weak, causing standard inference procedures to become unreliable. Learning also induces persistent dynamics, and this makes the distribution of estimators and test statistics non-standard. Valid inference can be conducted using the Anderson-Rubin statistic with appropriate choice of instruments. Application of this method to a typical new Keynesian sticky-price model with perpetual learning demonstrates its usefulness in practice.     

Stochastic modelling of herd behaviour indices

This paper proposes different diffusion processes to model herd behaviour indices such as the Herd Behaviour Index (HIX). These models arise by combining popular mean-reverting processes with simple algebraic functions mapping the definition domain of the underlying mean-reverting process to the unit interval. The so obtained Itô processes preserve, to some extent, the mean-reverting trend of the underlying process while satisfying the fundamental properties of the so-called herd behaviour indices. In a numerical study, we calibrate the different model settings to time series data for a period spanning from January 2000 until October 2009 and investigate their ability to predict the future behaviour of herd behaviour indices.     

Banking crises,labor reforms,and unemployment

Using a sample of 97 countries spanning the period 1980–2008, we estimate that banking crises have, on average, a large negative impact on unemployment. This effect, however, largely depends on the flexibility of labor market institutions: while in countries with more flexible labor markets the impact of banking crises is sharper but short-lived, in countries with more rigid labor markets the effect is initially more subdued but highly persistent. These effects are even larger for youth unemployment in the short term, and long-term unemployment in the medium term. Conversely, large upfront, or gradual but significant, comprehensive market reforms have a positive impact on unemployment, albeit only in the medium term.     

More strategies, more Nash equilibria

We show in this paper that for the class of two-player games with compact real intervals as strategy spaces and continuous and strictly quasi-concave payoff functions there exists a monotone relation between the size of strategy spaces and the number of Nash equilibria. These sufficient conditions for our theorem to hold are shown to be tight.     

Minimum Distance Estimation and Testing of DSGE Models from Structural VARs*

The aim of this paper is to complement the minimum distance estimation–structural vector autoregression approach when the weighting matrix is not optimal. In empirical studies, this choice is motivated by stochastic singularity or collinearity problems associated with the covariance matrix of impulse response functions. Consequently, the asymptotic distribution cannot be used to test the economic model's fit. To circumvent this difficulty, we propose a simple simulation method to construct critical values for the test statistics. An empirical application with US data illustrates the proposed method.     

Platform Pricing Structure and Moral Hazard

We study pricing by a two‐sided platform when it faces moral hazard on the sellers' side. In doing so, we introduce an equilibrium notion of platform reputation in an infinite horizon model. We find that with transaction fees only, the platform cannot eliminate the loss of reputation induced by moral hazard. If registration fees can be levied, moral hazard can be overcome. The registration fee determines the participation threshold of sellers and extracts them, whereas (lower) transaction fees provide incentives for good behavior. This provides a motivation for platforms to use registration fees in addition to transaction fees.     

Adopting telework: The causal impact of working from home on subjective well-being

We study the impact of work from home (WFH) on subjective well-being during the Covid period, where self-selection of individuals into telework is ruled out, at least part of the time, by stay-at-home orders. We use a difference-in-differences approach with individual fixed effects and identify the specific impact of switching to telecommuting, separately from any other confounding factor. In particular, our identification strategy avoids the influence of interpersonal heterogeneity by exploiting the multiple entries into WFH, by the same individuals, at different times. On average over the period, switching to WFH, especially full-time, worsens mental health. We also find a positive but imprecisely measured impact of part-time WFH on life satisfaction. However, this hides a dynamic evolution, whereby the initial deterioration gives place to an adaptation process after a couple of months. We also uncover a particularly pronounced fall in subjective well-being of women with children, especially in the first months; this could be associated with home-schooling.     

Firms and the global crisis: French exports in the turmoil

Global trade contracted quickly and severely during the global crisis. This paper uses a unique dataset of French firms to match export data to firm-level credit constraints and shows that most of the 2008–2009 trade collapse was due to the unprecedented demand shock and to product characteristics. While all firms have been affected by the crisis, the effect on large firms has been mainly at the intensive margin and has resulted in a smaller portfolio of products being offered to export destinations. The effect on smaller exporters has been to reduce the range of destinations served or to stop exporting altogether. Credit constraints have been an added aggravation for firms active in high financial dependence sectors. However, the share of credit constrained firms is small and their number has not increased hugely during the crisis, with the result that the overall impact of credit constraints on trade has been limited.