Essays on employment / education, investment in education and student achievement

Méthodologie: Modèle de régression quantile de variable instrumentale pour données de Panel utilisant la fonction de production partielle

Essays on firm behaviour in the euro area

This thesis examines firms' real decisions using a large panel of unquoted euro area firms over the period 2003-2011. To this end, this thesis is composed of five chapters in which three are the main empirical chapters. They assess the dimensions of firm behaviour across different specifications. Each of these chapters provide a detailed discussion on the contribution, theoretical and empirical background as well as the panel data techniques which are implemented. Chapter 1 describes the introduction and outline of the thesis. Chapter 2 presents an empirical analysis on the link between financial pressure and firms' employment level. In this set-up, it is explored the strength of financial pressure during the financial crisis. It is also tested whether this effect has a different impact for financially constrained and unconstrained firms in the periphery and non-periphery regions. The results of this chapter denote that financial pressure exerts a negative impact on firms' employment decisions and that this effect is stronger during the crisis for financially constrained firms in the periphery. Chapter 3 analyses the cash policies of private and public firms. Controlling for firm size and other standard variables in the literature of cash holdings, empirical findings suggest that private firms hold higher cash reserves than their public counterparts indicating a greater precautionary demand for cash by the former. The relative difference between these two type of firms decreases (increases) the higher (lower) is the the level of financial pressure. The findings are robust to various model specifications and over different sub-samples. Overall, this chapter shows the relevance of firms' size. Taken together, the findings of Chapter 3 are in line with the early literature on cash holdings and contradict the recent studies, which find that the precautionary motive to hold cash is less pronounced for private firms than for public ones. Chapter 4 undertakes an investigation on the relation between firms' stocks of inventories and trade credit (i.e. extended and taken) whilst controlling for the firms' size, the characteristics of the goods transacted, the recent financial crisis and the development of the banking system. The main findings provide evidence of a trade-off between trade credit extended and firms' stock of inventories. In other words, firms' prefer to extend credit in the form of stocks to their financially constrained customers to avoid holdings costly inventories and to increase their sales levels. The provision of trade credit by the firms also depends on the characteristics of the goods transacted. This impact is stronger during the crisis. Larger and liquid banking systems reduce the trade-off between the volume of stocks of inventories and the amount sold on credit. Trade credit taken is not affected by firms' stock of inventories. Chapter 5 presents the conclusions of the thesis. It provides the main contributions, implications and future research of each empirical chapter.

Estudio de empresas de sectores hegemónicos en Colombia para los años 2013 y 2014

Este documento evidencia las posiciones hegemónicas que han llegado a ocupar las empresas más poderosas del país, basándose en el estudio de datos cuantitativos del conteo de las cien empresas con mejores ventas para los años 2013 y 2014, según la revista Gerente. Se usan cinco variables: ventas totales, activos, pasivos, patrimonio y utilidades netas. En la primera sección, se hace una revisión bibliográfica que conecta el origen de la hegemonía en un panorama económico con la influencia del neoliberalismo y la globalización en el actual tejido industrial colombiano. Posteriormente, se realiza una explicación sobre la metodología aplicada para el estudio de la base de datos; la cual es seguida por una exposición de los resultados obtenidos a partir de herramientas estadísticas como el análisis de correlación lineal, quintiles y variaciones porcentuales. Finalmente, se aborda el Programa de Transformación Productiva, esto con el objetivo de mostrar los puntos focales que necesitan especial atención para lograr catalizar el desarrollo económico de Colombia.

Civil conflict and voting behavior : evidence from Colombia

¿Cuáles son los efectos de la guerra sobre el comportamiento político? Colombia es un caso interesante en el que el conflicto y las elecciones coexisten y los grupos armados ilegales intencionalmente afectan los resultados electorales. Sin embargo, los grupos usan diferentes estrategias para alterar estos resultados. Este artículo argumenta que los efectos diferenciales de la violencia sobre los resultados electorales son el resultado de estrategias deliberadas de los grupos ilegales, que a su turno, son consecuencia de las condiciones militares que difieren entre ellos. Usando datos panel de las elecciones al Senado de 1994 a 2006 y una aproximación por variables instrumentales para resolver posibles problemas de endogenidad, este artículo muestra que la violencia guerrillera disminuye la participación electoral, mientras que la violencia paramilitar no tiene ningún efecto sobre la participación pero reduce la competencia electoral y beneficia a nuevos partidos no-tradicionales. Esto es consistente con la hipótesis de que la estrategia de la guerrilla es sabotear las elecciones, mientras que los paramiltares establecen alianzas con ciertos candidatos.

Modelling spillover effects in spatial stochastic frontier analysis

In the last two decades, authors have begun to expand classical stochastic frontier (SF) models in order to include also some spatial components. Indeed, firms tend to concentrate in clusters, taking advantage of positive agglomeration externalities due to cooperation, shared ideas and emulation, resulting in increased productivity levels. Until now scholars have introduced spatial dependence into SF models following two different paths: evaluating global and local spatial spillover effects related to the frontier or considering spatial cross-sectional correlation in the inefficiency and/or in the error term. In this thesis, we extend the current literature on spatial SF models introducing two novel specifications for panel data. First, besides considering productivity and input spillovers, we introduce the possibility to evaluate the specific spatial effects arising from each inefficiency determinant through their spatial lags aiming to capture also knowledge spillovers. Second, we develop a very comprehensive spatial SF model that includes both frontier and error-based spillovers in order to consider four different sources of spatial dependence (i.e. productivity and input spillovers related to the frontier function and behavioural and environmental correlation associated with the two error terms). Finally, we test the finite sample properties of the two proposed spatial SF models through simulations, and we provide two empirical applications to the Italian accommodation and agricultural sectors. From a practical perspective, policymakers, based on results from these models, can rely on precise, detailed and distinct insights on the spillover effects affecting the productive performance of neighbouring spatial units obtaining interesting and relevant suggestions for policy decisions.

Modeling usage of medical care services: the medical expenditure panel survey data, 1996-2000

We explore the determinants of usage of six different types of health care services, using the Medical Expenditure Panel Survey data, years 1996-2000. We apply a number of models for univariate count data, including semiparametric, semi-nonparametric and finite mixture models. We find that the complexity of the model that is required to fit the data well depends upon the way in which the data is pooled across sexes and over time, and upon the characteristics of the usage measure. Pooling across time and sexes is almost always favored, but when more heterogeneous data is pooled it is often the case that a more complex statistical model is required.

Is real GDP stationary? Evidence from a panel unit root test with cross-sectional dependence and historical data

We use historical data that cover more than one century on real GDP for industrial countries and employ the Pesaran panel unit root test that allows for cross-sectional dependence to test for a unit root on real GDP. We find strong evidence against the unit root null. Our results are robust to the chosen group of countries and the sample period. Key words: real GDP stationarity, cross-sectional dependence, CIPS test. JEL Classification: C23, E32

The effects of gender segregation at the establishment level: an empirical analysis using a panel of matched employer-employee data

This paper studies the relationship between segregation of women across establish- ments and the wages of males and females. To investigate this issue empirically we use a panel of matched employer-employee data from Brazil. Various longitudinal models are used to assess the wage impact of establishment gender segregation. Overall, the results indicate that the e ect of establishment female proportion on the wages of males and females is negative. We also compare these longitudinal results with cross-section estimates, which are the usual ones obtained in the related literature. This com- parison suggests that unmeasured, time-invariant worker- and establishment-speci c e ects are correlated with the establishment female composition.

Analyzing Panel Count Data with Informative Observation Times

In this paper, we study panel count data with informative observation times. We assume nonparametric and semiparametric proportional rate models for the underlying recurrent event process, where the form of the baseline rate function is left unspecified and a subject-specific frailty variable inflates or deflates the rate function multiplicatively. The proposed models allow the recurrent event processes and observation times to be correlated through their connections with the unobserved frailty; moreover, the distributions of both the frailty variable and observation times are considered as nuisance parameters. The baseline rate function and the regression parameters are estimated by maximizing a conditional likelihood function of observed event counts and solving estimation equations. Large sample properties of the proposed estimators are studied. Numerical studies demonstrate that the proposed estimation procedures perform well for moderate sample sizes. An application to a bladder tumor study is presented to illustrate the use of the proposed methods.

Cervical soft tissue imaging using a mobile CBCT scanner with a flat panel detector in comparison with corresponding CT and MRI data sets

OBJECTIVE: The aim of this study was to evaluate soft tissue image quality of a mobile cone-beam computed tomography (CBCT) scanner with an integrated flat-panel detector. STUDY DESIGN: Eight fresh human cadavers were used in this study. For evaluation of soft tissue visualization, CBCT data sets and corresponding computed tomography (CT) and magnetic resonance imaging (MRI) data sets were acquired. Evaluation was performed with the help of 10 defined cervical anatomical structures. RESULTS: The statistical analysis of the scoring results of 3 examiners revealed the CBCT images to be of inferior quality regarding the visualization of most of the predefined structures. Visualization without a significant difference was found regarding the demarcation of the vertebral bodies and the pyramidal cartilages, the arteriosclerosis of the carotids (compared with CT), and the laryngeal skeleton (compared with MRI). Regarding arteriosclerosis of the carotids compared with MRI, CBCT proved to be superior. CONCLUSIONS: The integration of a flat-panel detector improves soft tissue visualization using a mobile CBCT scanner.

Outpatient prescription drugs : data collection and editing in the 1996 Medical Expenditure Panel Survey (HC-010A).

"June 2001."

Elevated-temperature properties of carbon steel. Data compiled by and issued under the auspices of the Data and Publications Panel of the ASTM-ASME Joint Committee on Effect of Temperature on the Properties of Metals.

Mode of access: Internet.