Andrés Ramírez Hassan

The Impact of Subsidized Health Insurance on the Poor in Colombia: Evaluating the Case of Medellín

Este trabalho utiliza modelos de dados binarios e de contagem com uma variavel indicadora endogena para avaliar o efeito do programa de saude em Medellin (Colombia). Encontrou-se um impacto significativo do programa subsidiado, que abrange principalmente a populacao pobre, sobre o uso de assistencia medica preventiva e de internacao, o que pode ter um impacto negativo sobre as situacoes financeiras do programa. Especificamente, estimativas econometricas da utilizacao de cuidados de saude indicam que ha selecao e risco moral. Esses fatos sugerem que o programa pode melhorar sua cobertura se forem criados mecanismos para diminuir o efeito de risco moral individual.

A Multi-Stage Almost Ideal Demand System: The Case of Beef Demand in Colombia

The main objective in this paper is to obtain reliable long-term and short-term elasticities estimates of the beef demand in Colombia using quarterly data since 1998 until 2007. However, complexity on the decision process of consumption should be taken into account, since expenditure on a particular good is sequential. In the case of beef demand in Colombia, a Multi-Stage process is proposed based on an Almost Ideal Demand System (AIDS). The econometric novelty in this paper is to estimate simultaneously all the stages by the Generalized Method of Moments to obtain a joint covariance matrix of parameters estimates in order to use the Delta Method for calculating the standard deviation of the long-term elasticities estimates. Additionally, this approach allows us to get elasticities estimates in each stage, but also, total elasticities which incorporates interaction between stages. On the other hand, the short-term dynamic is handled by a simultaneous estimation of the Error Correction version of the model; therefore, Monte Carlo simulation exercises are performed to analyse the impact on beef demand because of shocks at different levels of the decision making process of consumers. The results indicate that, although the total expenditure elasticity estimate of demand for beef is 1.78 in the long-term and the expenditure elasticity estimate within the meat group is 1.07, the total short-term expenditure elasticity is merely 0.03. The smaller short-term reaction of consumers is also evidenced on price shocks; while the total own price elasticity of beef is -0.24 in the short-term, the total and within meat group long-term elasticities are -1.95 and -1.17, respectively.

The Roots of Export Diversification

Countries with diversi ed export baskets take advantage of various bene ts, which are said to foster and stabilize economic growth directly and through indirect channels (e.g. reduced income volatility, positive externalities, spillover e ects). This is especially important in the context of developing economies. However, identifying the true determinants of export diversifi cation is di cult as there exists no comprehensive theoretical or empirical framework to capture all potential factors in their entirety. This paper uses Bayesian Model Averaging to uncover the true long-term roots of export diversi cation among 43 potential determinants,and thus 2 potential models. Our results suggest that only four factors are important in predicting export diversi cation levels over the long run: natural resource rents as a percentage of GDP (100 % posterior inclusion probability), primary school enrollment rates (96 %), population size (25 %), and foreign direct investment levels (17 %). Many prominent candidates turn out to be insigni cant in determining diversi cation levels. Neither policy-related variables (e.g. tari s, freedom from trade regulations or democracy) nor macroeconomic factors (such as trade openness, terms of trade or domestic investment levels) nor geographical remoteness (whether the country is an island or landlocked) play a role. Various robustness checks con rm our results.

Co-movements between Latin American and U.S. stock markets: convergence after the financial crisis

Currently, the world is facing a continuous process of integration in di fferent aspects and fi nancial markets are no exception to this development. Despite the fact that global integration is gradual, one can fi nd some specfi c events that might help to accelerate this trend. This paper shows that after the fi nancial crisis of 2008, which mainly occurred in the United States, the Latin American stock markets exhibit a higher level of convergence, measured by the correlation between the annual returns of their stock market indices. Additionally, we find convergence in the coe ficient of sensitivity between Latin American and U.S. stock markets, using dynamic linear models at the regional level. In particular, we uncover consistent movements in the levels of sensitivity between the daily annual returns of the Latin American indices and the S&P index after the fi nancial crisis. This kind of convergence might be a positive sign to accelerate the integration process in Latin America stock markets, which has had a slow development since its beginning a few years ago.

Welfare Gains of the Poor: An Endogenous Bayesian Approach with Spatial Random Effects

We introduce a Bayesian instrumental variable procedure with spatial random effects that handles endogeneity, and spatial dependence with unobserved heterogeneity. We take into account the endogeneity through a system of simultaneous equations where a conditional correlation between the stochastic errors captures the endogeneity, and exclusion restrictions are used to treat endogenous regressors. In addition, we propose a Bayesian hierarchical spatial framework to model spatial dependence and heterogeneity. A Gibbs sampling algorithm is used to draw samples from all our conditional posterior distributions. We find through a limited Monte Carlo experiment that our proposal works well in terms of point and interval estimates, as well as prediction, compared with other possible alternatives. Taking advantage of the fact that a Bayesian framework permits easily performing statistical inference related to complicated non-linear functions of parameter estimates, we apply our method to analyze the welfare effects on the poorest households generated by a process of electricity tariff unification. In particular, we deduce an Equivalent Variation measure from a logarithmic demand function and a budget constraint for a two-tiered pricing scheme. We find the posterior distribution of the Equivalent Variation, and estimate the welfare implications in a context where electricity tariffs decreased by as much as 17.53%. We find that 10% of the poorest municipalities attained welfare gains above 2% of their initial income.

Determining the Optimal Selling Time of Cattle: A Stochastic Dynamic Programming Approach

The world meat market demands competitiveness and optimal livestock replacement decisions can help to achieve this goal. We introduce a novel discrete stochastic dynamic programming framework to support a manager’s decision-making process of whether to sell or keep fattening animals in the beef sector. In particular, our proposal uses a non-convex value function, combining both economic and biological variables, and involving uncertainty with regard to price fluctuations. Our methodology is very general, so practitioners can apply it in different regions around the world. We illustrate the model’s convenience with an empirical application, finding that our methodology generates better results than actions based on empirical experience.

A Frequency Domain Test for a Spatial Unit Root Process

Stationarity is a common assumption in statistical inference when data come from a random field, but this hypothesis has to be checked. In this paper, we build a frequency domain statistical test to check a unit root for a spatial autoregressive model, and find its asymptotic distribution. Later, we use Monte Carlo simulations to obtain the small sample properties of the proposed statistical test, and we find that the size of the test is good, and the power of the test improves if the spatial autocorrelation coefficient decreases. Additionally, we find that the size of our test is better than other spatial unit root tests when the data generating process is not a spatial autoregressive model. Finally, we propose a methodology to use frequency domain tests in regional data, and we use it to do an application. Specifically, we study data of electricity demand in the Department of Antioquia (Colombia), and find that statistical evidence based on different tests suggests that electricity consumption does not have a spatial unit root; as a consequence, parameter estimates are sensible. Specifically, we find that the price elasticity of electricity demand is -1.150 while the income elasticity is 0.408.

Determinantes Del Rendimiento Académico En Colombia: Pruebas ICFES Saber 11, 2009 (Academic Performance Determinants in Colombia: ICFES Saber 11, 2009 Exam)

Spanish Abstract: En este trabajo se utilizan los resultados obtenidos por los estudiantes en las áreas de matemáticas y lenguaje de las pruebas ICFES Saber 11º del segundo semestre de 2009, como medio para identificar los determinantes del rendimiento académico en Colombia. Para ello, se utiliza el modelo Logit Ordenado Generalizado. Los resultados obtenidos enseñan la relevancia que tienen las variables socioeconómicas en el desempeño para ambas áreas. En particular, las variables nivel de ingreso y nivel de escolaridad de los progenitores, las cuales presentan un impacto positivo y significativo en el resultado de las pruebas. Igualmente se encuentra un impacto significativo de la jornada académica; los bachilleres de jornada completa obtienen puntajes más altos comparados con los estudiantes pertenecientes a otras jornadas. Este resultado debe tomarse en consideración a la hora de establecer políticas de cobertura fundamentadas en la partición de la jornada, y no en la creación de nuevas instituciones. English Abstract: In this paper, we use the results obtained by students in math and language test ICFES Saber 11th of the second half of 2009, the aim is to identify the determinants of academic performance in Colombia. We use the Generalized Ordered Logit estimation procedure, and find a great relevance of socioeconomic variables in the performance for both areas. In particular, the income and the education level of parents have a significant positive impact on the outcome of the test. Additionally, it was found that the time in the school is statistically significant. Specifically, full-time students get better performance in the test than part-time students. This is very important in order to determine coverage education policies based on reducing the time of students in school rather than creating new institutions.

Un Sistema Casi Ideal De Demanda Para El Gasto En Colombia: Una Estimación Utilizando El Método Generalizado De Los Momentos En El Periodo 1968-2007 (An Almost Ideal Expenditure Demand System in Colombia: Generalized Moments Estimation in the Period 1968-2007)

Spanish Abstract: El presente trabajo utiliza una Aproximación Lineal del Modelo Casi Ideal de Demanda (Linear Approximation/Almost Ideal Demand System) para examinar los gastos de los colombianos en la canasta básica, y estimar sus respectivas elasticidades precio y gasto, a partir de datos de series de tiempo para Colombia en el período de 1968-2007. Las elasticidades gasto y precio, compensadas y no compensadas, presentan los signos esperados, siendo en su mayoría menores en valor absoluto a uno y estadísticamente significativas. English Abstract: This work uses a Linear Approximation of the Almost Ideal Demand System (LA/AIDS) to examine Colombians expenditure in daily needs and to estimate the respective expenditure and price elasticities using Colombian time series from 1968 to 2007. The results show that the expenditure and price elasticities (compensated and not compensated) have the expected signs, most of them being less than one in absolute value and statistically significant.

An Ordered Categorical Response Model with Endogenous Switching: Simulation Exercises and an Application to State Health

We develop and estimate a full information maximum likelihood ordered categorical response model with endogenous switching. Simulation exercises show that estimated parameters are unbias and consistent. And application to Internet access indicates that there are selection and moral hazard.