Nonparametric specification tests for conditional duration models

This paper deals with the testing of autoregressive conditional duration (ACD) models by gauging the distance between the parametric density and hazard rate functions implied by the duration process and their non-parametric estimates. We derive the asymptotic justification using the functional delta method for fixed and gamma kernels, and then investigate the finite-sample properties through Monte Carlo simulations. Although our tests display some size distortion, bootstrapping suffices to correct the size without compromising their excellent power. We show the practical usefulness of such testing procedures for the estimation of intraday volatility patterns.

Non- parametric specification tests for conditional duration models

This paper deals with the estimation and testing of conditional duration models by looking at the density and baseline hazard rate functions. More precisely, we foeus on the distance between the parametric density (or hazard rate) function implied by the duration process and its non-parametric estimate. Asymptotic justification is derived using the functional delta method for fixed and gamma kernels, whereas finite sample properties are investigated through Monte Carlo simulations. Finally, we show the practical usefulness of such testing procedures by carrying out an empirical assessment of whether autoregressive conditional duration models are appropriate to oIs for modelling price durations of stocks traded at the New York Stock Exchange.

On the positive correlation between income inequality and unemployment

Several empirical studies in the literature have documented the existence of a positive correlation between income inequalitiy and unemployment. I provide a theoretical framework under which this correlation can be better understood. The analysis is based on a dynamic job search under uncertainty. I start by proving the uniqueness of a stationary distribution of wages in the economy. Drawing upon this distribution, I provide a general expression for the Gini coefficient of income inequality. The expression has the advantage of not requiring a particular specification of the distribution of wage offers. Next, I show how the Gini coefficient varies as a function of the parameters of the model, and how it can be expected to be positively correlated with the rate of unemployment. Two examples are offered. The first, of a technical nature, to show that the convergence of the measures implied by the underlying Markov process can fail in some cases. The second, to provide a quantitative assessment of the model and of the mechanism linking unemployment and inequality.

Trade liberalization and industrial concentration: evidence from Brazil

This paper applies an endogenous lobby formation model to explain the extent of trade protection granted to Brazilian manufacturing industries during the 1988- 1994 trade liberalization episode. Using a panel data set covering this period, we find that even in an environment in which a major regime shift has been introduced, more concentrated sectors have been able to obtain policy advantages, that lead to a reduction in international competition. The importance of industry structure appears to be substantial: In our baseline specification, an increase in concentration by 20% leads to an increase in protection by 5%-7%.

Foreign direct investment spillovers in Portugal: additional lessons from a country study

This paper investigates the impact of FDI on the productivity of Portuguese manufacturing sectors. Model specification is improved by considering the choice of the most appropriate interval of the technological gap for spillovers diffusion. We also allow for sectoral variation in the coefficients of the spillover effect; idiosyncratic sectoral factors are identified by means of a fixed effects model. Inter-sectoral positive spillover effects are examined. Significant spillovers require a proper technological differential between foreign and domestic producers and favourable sectoral characteristics. They may occur in modern industries in which the foreign firms have a clear, but not too sharp, edge on the domestic ones. Agglomeration effects are also one pertinent specific influence.

Testing production functions used in empirical growth studies

We estimate and test two alternative functional forms, which have been used in the growth literature, representing the aggregate production function for a panel of countries: the model of Mankiw, Romer and Weil (Quarterly Journal of Economics, 1992), and a mincerian formulation of schooling-returns to skills. Estimation is performed using instrumental-variable techniques, and both functional forms are confronted using a Box-Cox test, since human capital inputs enter in levels in the mincerian specification and in logs in the extended neoclassical growth model.

Evaluating Value-at-Risk models via Quantile regressions

This paper is concerned with evaluating value at risk estimates. It is well known that using only binary variables to do this sacrifices too much information. However, most of the specification tests (also called backtests) avaliable in the literature, such as Christoffersen (1998) and Engle and Maganelli (2004) are based on such variables. In this paper we propose a new backtest that does not realy solely on binary variable. It is show that the new backtest provides a sufficiant condition to assess the performance of a quantile model whereas the existing ones do not. The proposed methodology allows us to identify periods of an increased risk exposure based on a quantile regression model (Koenker & Xiao, 2002). Our theorical findings are corroborated through a monte Carlo simulation and an empirical exercise with daily S&P500 time series.

Foreign direct investment spillovers: what can we learn from portuguese data?

This paper investigates the impact of foreign direct investment on the productivity performance of domestic firms in Portugal. The data comprise nine manufacturing sectors for the period 1992-95. Relatively to previous studies, model specification is improved by taking into consideration several aspects: the influence of the “technological gap” on spill-overs diffusion and the choice of its most appropriate interval; sectoral variation in the coefficients of the spill-overs effect; identification of constant, idiosyncratic sectoral factors by means of a fixed effects model; and the search for inter-sectoral positive spillover effects. The relationship between domestic firms productivity and the foreign presence does take place in a positive way, only if a proper technology differential between the foreign and domestic producers exists and the sectoral characteristics are favourable. In broad terms, spillovers diffusion is associated to modern industries in which the foreign owned establishments have a clear, but not too sharp, edge on the domestic ones. Besides, other specific sectoral influences can be pertinent; agglomerative location factors being one example.

Testing production functions used in empirical growth studies

We estimate and test two alternative functional forms representing the aggregate production function for a panel of countries: the extended neoclassical growth model, and a mincerian formulation of schooling-returns to skills. Estimation is performed using instrumentalvariable techniques, and both functional forms are confronted using a Box-Cox test, since human capital inputs enter in levels in the mincerian specification and in logs in the extended neoclassical growth model. Our evidence rejects the extended neoclassical growth model in favor of the mincerian specification, with an estimated capital share of about 42%, a marginal return to education of about 7.5% per year, and an estimated productivity growth of about 1.4% per year. Differences in productivity cannot be disregarded as an explanation of why output per worker varies so much across countries: a variance decomposition exercise shows that productivity alone explains 54% of the variation in output per worker across countries.

Measures of the welfare cost of inflation: a complete ordering

This paper presents three contributions to the literature on the welfare cost of ináation. First, it introduces a new sensible way of measuring this cost - that of a compensating variation in consumption or income, instead of the equivalent variation notion that has been extensively used in empirical and theoretical research during the past fiftt years. We Önd this new measure to be interestingly related to the proxy measure of the shopping-time welfare cost of ináation introduced by Simonsen and Cysne (2001). Secondly, it discusses for which money-demand functions this and the shopping-time measure can be evaluated in an economically meaningful way. And, last but not least, it completely orders a comprehensive set of measures of the welfare cost of ináation for these money-demand specification. All of our results are extended to an economy in which there are many types of monies present, and are illustrated with the log-log money-demand specification.

Política de compras e contratações: trajetória e mudanças na administração pública federal brasileira

A tese analisa as mudanças da política de compras e contratações da administração pública federal brasileira descrevendo de forma sistemática os seis casos nos quais as regras e procedimentos sofrem alteração substancial, na forma de leis gerais ou estatutos: a centralização das compras no período Vargas, em dois momentos decisivos (1931 e 1940); a revisão das regras de licitação pelo Decreto-lei n. 200, no contexto da reforma administrativa do governo Castello Branco; a edição de um estatuto das licitações (o Decreto-lei n 2.300) no governo Sarney; a aprovação no Legislativo de uma lei de licitações voltada para o combate à corrupção e ao direcionamento dos contratos públicos (Lei 8.666); a tentativa frustrada de uma nova lei alinhada com a reforma gerencial do primeiro governo Fernando Henrique Cardoso e a criação do pregão como nova modalidade de licitação, em 2000. A pesquisa focaliza o processo político de formulação dos problemas, especificação de soluções e tomada de decisão, com base no modelo de John Kingdon, desdobrando a análise em fluxos do processo político, dos problemas emergentes e das soluções, em cada contexto histórico específico. Os seis casos são descritos por meio de narrativas estruturadas e comparados a partir das categorias do modelo teórico para elucidar como se desenvolveu o processo de mudança, quais os atores relevantes, idéias, modelos e eventos políticos que explicam suas circunstâncias e resultado.

Sacrifice and efficiency of the income tax schedule

We investigate the efficiency of equal sacrifice tax schedules in an economy which primitives are exactly those in Mirrlees (1971): a continuum of individuals with identical preferences defined over consumption and leisure who differ with respect to their labor market productivity. Using a separable specification for preferences we derive the minimum equal sacrifice allocation and recover the tax schedule that implements it. The separable specification allows us to use the methodology developed by Werning (2007b) to check whether the schedule is efficient, that is, whether there is no alternative tax schedule that raises more revenue while delivering less utility to no one. We find that inefficiency does not arise for most parametrizations we use to approximate the US economy. For the few cases for which inefficiency does arise, it does so only for very high levels of income and marginal tax rates.

Fundamentos da psicologia social

O tema central deste estudo é o dos fundamentos da Psicologia Social. Neste sentido, foram examinados pressupostos ontológicos, epistemológicos, lógicos e axiológicos mas, também, as bases conceituais, teóricas e metodológicas deste setor da Psicologia contemporânea. A justificar este empreendimento, encontram-se duas suposições: a de que qualquer ciência é inexoravelmente construída sobre postulados metafísicos e lógicos, e a de que a falta de clareza em relação a estes impede a instalação de programas de pesquisa consequentes. Os objetivos colimados na consecução deste trabalho podem ficar assim discriminados: caracterização da Psicologia social; análise de suas bases filosóficas e lógicas; especificação da origem e classificação dos conceitos psicossociológicos; avaliação do estágio de teorização atingido na Psicologia Social; e discussão de aspectos epistemológicos da metodologia de pesquisa psicossociológica. Este texto pode ser classificado como filosófico. E pode sê-lo em virtude da natureza dos problemas submetidos à investigação e da metodologia empregada para este fim. São três as conclusões mais relevantes: em primeiro lugar, a de que em todas as ciências sociais e humanas, por subsistirem diversos pressupostos antropológicos ou imagens do Homem, cabe fomentar o pluralismo teórico; a de que nas disciplinas-psicológicas, a orientação nomotética - uma dentre várias alternativas doutrinárias existentes - deve continuar a ser desenvolvida; e, finalmente, a de que a Psicologia Social insere-se como elemento importante no processo de autoconsciência do Homem.

Cash flow and discount rate risk decomposition and ICAPM for the US and brazilian stock markets

Esse trabalho é uma aplicação do modelo intertemporal de apreçamento de ativos desenvolvido por Campbell (1993) e Campbell e Vuolteenaho (2004) para as carteiras de Fama-French 2x3 brasileiras no period de janeiro de 2003 a abril de 2012 e para as carteiras de Fama-French 5x5 americanas em diferentes períodos. As varíaveis sugeridas por Campbell e Vuolteenaho (2004) para prever os excessos de retorno do mercado acionário americano no period de 1929 a 2001 mostraram-se também bons preditores de excesso de retorno para o mercado brasileiro no período recente, com exceção da inclinação da estrutura a termo das taxas de juros. Entretanto, mostramos que um aumento no small stock value spread indica maior excesso de retorno no futuro, comportamento que não é coerente com a explicação para o prêmio de valor sugerida pelo modelo intertemporal. Ainda, utilizando os resíduos do VAR preditivo para definir o risco de choques de fluxo de caixa e de choques nas taxas de desconto das carteiras de teste, verificamos que o modelo intertemporal resultante não explica adequadamente os retornos observados. Para o mercado norte-americano, concluímos que a abilidade das variáveis propostas para explicar os excessos de retorno do mercado varia no tempo. O sucesso de Campbell e Vuolteenaho (2004) em explicar o prêmio de valor para o mercado norte-americano na amostra de 1963 a 2001 é resultado da especificação do VAR na amostra completa, pois mostramos que nenhuma das varíaveis é um preditor de retorno estatisticamente significante nessa sub-amostra.

Estimation of DSGE Models: A Monte Carlo Analysis

Neste trabalho investigamos as propriedades em pequena amostra e a robustez das estimativas dos parâmetros de modelos DSGE. Tomamos o modelo de Smets and Wouters (2007) como base e avaliamos a performance de dois procedimentos de estimação: Método dos Momentos Simulados (MMS) e Máxima Verossimilhança (MV). Examinamos a distribuição empírica das estimativas dos parâmetros e sua implicação para as análises de impulso-resposta e decomposição de variância nos casos de especificação correta e má especificação. Nossos resultados apontam para um desempenho ruim de MMS e alguns padrões de viés nas análises de impulso-resposta e decomposição de variância com estimativas de MV nos casos de má especificação considerados.