High-School Dropouts and Transitory Labor Market Shocks: The Case of the Spanish Housing Boom

This paper addresses the implications of transitory changes in labor market conditions for low versus high educated workers on the decision to acquire education. To identify this effect, I use the improvement in the labor market prospects of low educated workers motivated by the increases in employment and wages in the construction sector during the recent housing boom. The estimation strategy is based on the fact that changes in the labor market driven by the construction sector affect only men. Increases in construction activity are found to increase men's propensity to drop out of high-school, relative to women. According to this finding, policies promoting education should strengthen when in the presence of transitory shocks in the labor market that make dropping out more attractive.High-school dropout; housing boom; Spain

High-School Dropouts and Transitory Labor Market Shocks: The Case of the Spanish Housing Boom

This paper addresses the implications of transitory changes in labor market conditions for low versus high educated workers on the decision to acquire education. To identify this effect, I use the improvement in the labor market prospects of low educated workers motivated by the increases in employment and wages in the construction sector during the recent housing boom. The estimation strategy is based on the fact that changes in the labor market driven by the construction sector affect only men. Increases in construction activity are found to increase men's propensity to drop out of high-school, relative to women. According to this finding, policies promoting education should strengthen when in the presence of transitory shocks in the labor market that make dropping out more attractive.high-school dropout, housing boom, Spain

A Reduction Method for Higher Order Variational Equations of Hamiltonian Systems

Let $\mathbf{k}$ be a differential field and let $[A]\,:\,Y'=A\,Y$ be a linear differential system where $A\in\mathrm{Mat}(n\,,\,\mathbf{k})$. We say that $A$ is in a reduced form if $A\in\mathfrak{g}(\bar{\mathbf{k}})$ where $\mathfrak{g}$ is the Lie algebra of $[A]$ and $\bar{\mathbf{k}}$ denotes the algebraic closure of $\mathbf{k}$. We owe the existence of such reduced forms to a result due to Kolchin and Kovacic \cite{Ko71a}. This paper is devoted to the study of reduced forms, of (higher order) variational equations along a particular solution of a complex analytical hamiltonian system $X$. Using a previous result \cite{ApWea}, we will assume that the first order variational equation has an abelian Lie algebra so that, at first order, there are no Galoisian obstructions to Liouville integrability. We give a strategy to (partially) reduce the variational equations at order $m+1$ if the variational equations at order $m$ are already in a reduced form and their Lie algebra is abelian. Our procedure stops when we meet obstructions to the meromorphic integrability of $X$. We make strong use both of the lower block triangular structure of the variational equations and of the notion of associated Lie algebra of a linear differential system (based on the works of Wei and Norman in \cite{WeNo63a}). Obstructions to integrability appear when at some step we obtain a non-trivial commutator between a diagonal element and a nilpotent (subdiagonal) element of the associated Lie algebra. We use our method coupled with a reasoning on polylogarithms to give a new and systematic proof of the non-integrability of the H\'enon-Heiles system. We conjecture that our method is not only a partial reduction procedure but a complete reduction algorithm. In the context of complex Hamiltonian systems, this would mean that our method would be an effective version of the Morales-Ramis-Sim\'o theorem.Comment: 15 page

A Reduced Form for Linear Differential Systems and its Application to Integrability of Hamiltonian Systems

Let $[A]: Y'=AY$ with $A\in \mathrm{M}_n (k)$ be a differential linear system. We say that a matrix $R\in {\cal M}_{n}(\bar{k})$ is a {\em reduced form} of $[A]$ if $R\in \mathfrak{g}(\bar{k})$ and there exists $P\in GL_n (\bar{k})$ such that $R=P^{-1}(AP-P')\in \mathfrak{g}(\bar{k})$. Such a form is often the sparsest possible attainable through gauge transformations without introducing new transcendants. In this article, we discuss how to compute reduced forms of some symplectic differential systems, arising as variational equations of hamiltonian systems. We use this to give an effective form of the Morales-Ramis theorem on (non)-integrability of Hamiltonian systems.Comment: 28 page

A Characterization of Reduced Forms of Linear Differential Systems

A differential system $[A] : \; Y'=AY$, with $A\in \mathrm{Mat}(n, \bar{k})$ is said to be in reduced form if $A\in \mathfrak{g}(\bar{k})$ where $\mathfrak{g}$ is the Lie algebra of the differential Galois group $G$ of $[A]$. In this article, we give a constructive criterion for a system to be in reduced form. When $G$ is reductive and unimodular, the system $[A]$ is in reduced form if and only if all of its invariants (rational solutions of appropriate symmetric powers) have constant coefficients (instead of rational functions). When $G$ is non-reductive, we give a similar characterization via the semi-invariants of $G$. In the reductive case, we propose a decision procedure for putting the system into reduced form which, in turn, gives a constructive proof of the classical Kolchin-Kovacic reduction theorem.Comment: To appear in : Journal of Pure and Applied Algebr

The Effect of Product Market Competition on Job Instability

This paper assesses the impact of product market competition on job instability as proxied by the use of fixed-term labor contracts. Using both worker data from the Spanish Labor Force Survey and firm data from the Spanish Business Strategies Survey, I show that job instability rises with competition. In particular, a one standard deviation increase in competition in an economic sector decreases the probability that a fixed-term worker gets an open-ended contract within that sector in a given year by more than 30%. The effect is identified by means of exogenous shifts in competition brought about by changes in legislation.fixed-term employment, product market competition, labor contract

Network Effects on Migrants' Remittances

This paper explores the existence of network effects in migrants’ remittance behavior. In this study, networks are defined as groups of immigrants from the same country that live in the same locality. Using the National Immigrant Survey, a unique database for Spain, immigrants are found to be more likely to remit and to remit more money if they belong to high remitting country groups. This finding sheds new light on the determinants of the decision to remit, as well as on the scope of immigrant networks.immigrant networks, remittances, Spain

Immigrant networks and remittances: Cheaper together?

We estimate the causal effects of immigrant networks on individuals’ remittance sending behavior for migrants from many different countries residing in Spain. Our methodology addresses typical issues that arise when estimating network effects: reverse causality, common unobserved factors, and self-selection. In particular, we instrument the size of networks by predicting the number of migrants in each location using the location's accessibility by distinct methods of transportation and information about how migrants from each country initially arrived in Spain. Our findings show that immigrants from above-average remitting countries remit more if they live in larger networks. For a subset of countries that receive large remittance flows from Spain, we show that migrants in larger networks are less likely to use most expensive remittance channels, and that cost spreads between the most expensive and cheapest remittance service provider are lower for countries characterized by stronger networks. Our results suggest that network effects could boost policy efforts to lower remittance pricesZoë Kuehn acknowledges financial support from the Ministerio de Economía Industria y Competitividad (ECO2017-82882-R) in Spai

Immigrants move where their skills are scarce: Evidence from English proficiency

This paper studies whether individuals tend to migrate to countries where their skills are scarce or abundant. Focusing on English language skills, we test whether immigrants who are proficient in English choose to move to countries where many or few individuals speak English. We use the introduction of English classes into compulsory school curricula as an exogenous determinant for English proficiency of migrants of different ages, and we consider cohort data on migration among 29 European countries, where English is not the official language and where labor mobility is essentially free. Our estimation strategy consists of refined comparisons of cohorts, and we control for all variables traditionally included in international migration models. We find that immigrants who are proficient in English move to countries where fewer individuals speak English, and where hence their skills are scarce. We also show that similar results hold for general skill