Modelos de elección discreta: una aplicación a la demanda por cupos universitarios en Colombia.

En este artículo se realiza una caracterización cuantitativa de la demanda de cupos universitarios por parte de bachilleres egresados de ciudades intermedias. Esto se realiza a través de modelos de elección discreta. Específicamente se encuentra que el número de programas ofrecidos aumenta la probabilidad de selección de las universidades por parte de los bachilleres, mientras que el ranking universitario está inversamente relacionado con dicha probabilidad. Por otra parte, se encuentra que la posición socioeconómica, medida a través del estrato, es una variable bastante explicativa de la elección universitaria; específicamente, los bachilleres provenientes de estratos bajos y medios tienden a optar por universidades públicas, mientras que los bachilleres de estratos altos seleccionan universidades privadas.This article makes a quantitative characterization of high school graduates from intermediate cities and their demand for university places. Specifically speaking, the results show that the number of programs offered by universities increases the probability of choosing the latter,whereas university ranking has an inverse relationship with that probability. On the other hand, the socio-economic state of high school graduates measured by their “estrato” is a variable that explains their choice of university. Specifically, the students from low and middle estratos show a strong trend in terms of choosing public universities, whereas those from high estratos prefer private universities

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 Colom- bia, a Multi-Stage process is proposed based on an Almost Ideal Demand System (AIDS). The econometric novelty in this paper is to estimate si- multaneously 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 elastic- ities 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 di erent 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 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 Colom- bia, a Multi-Stage process is proposed based on an Almost Ideal Demand System (AIDS). The econometric novelty in this paper is to estimate si- multaneously 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 elastic- ities 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 di erent 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

Una función de producción agregada para la economía colombiana: características e interacción entre el trabajo calificado, el trabajo no calificado y el capital, 1994–2005.

En este artículo se enseñan los resultados de las diversas elasticidades del trabajo calificado, el trabajo no calificado y el capital que se obtienen asumiendo una función de producción agregada translogarítmica para la economía colombiana. En general se encuentra que el trabajo calificado ha ganado participación al interior del proceso productivo en detrimento del trabajo no calificado y el capital. En general, los factores productivos son bienes normales, pero el trabajo calificado es el que reacciona más fuertemente ante expansión en el producto. Por otra parte, el trabajo no calificado es el factor productivo que presenta el mayor valor absoluto de la elasticidad precio de la demanda. Finalmente, se evidencia una relación de complementariedad entre el trabajo calificado y los otros dos factores, pero se presenta una relación de sustitubilidad entre el capital y el trabajo no calificado. Este acontecimiento microeconómico, unido al abaratamiento del costo de uso del capital y el encarecimiento del trabajo no calificado explican el poco descenso que ha experimentado la tasa de desempleo en la economía colombiana, pese al buen desempeño macroeconómico reciente.This paper estimates the skilled labor, unskilled labor and capital elasticities when it is assumed a translogarithmic production function for the Colombian economic. It is found that the skilled labor remuneration has risen its participation while the other production factors remuneration have gotten down. In general, the production factors are normal goods, but the skilled labor is the factor that has more reaction to changes to the aggregate production. On the other hand, the unskilled labor is the factor that has the highest price elasticity to the demand in absolute value. Finally, it is found that there is a complementary relation between the skilled labor and the other factors, but there is a substitution relation between the unskilled labor and the capital. These microeconomic facts join to the lower capital cost and the higher unskilled labor price explain the small fall in the unemployment rate while the macroeconomic environment is good

Una Panorámica Sobre la Evolución de la Deuda Externa Colombiana: ¡Juegos Ponzi! ¿Hasta Cuándo?

En este artículo se analiza la evolución temporal de la deuda externa colombiana durante las últimas décadas enfatizando en sus dos grandes componentes: la deuda pública y la deuda privada. El análisis se realizará a partir del estudio de la relación de la deuda con la cuenta corriente. La investigación considerará el componente permanente de las series en cuestión y la senda temporal de dicho componente a través del tiempo. Además, se estiman las implicaciones del comportamiento de la deuda desde la perspectiva de un modelo estocástico para una pequeña economía abierta y la restricción presupuestaria que se impone a partir de la prohibición de juegos Ponzi. Luego se realizan algunas reflexiones sobre la sostenibilidad de la deuda externa. Deuda externa, Componente permanente. - See more at: http://www.bdigital.unal.edu.co/27231/#sthash.wbtJBXEB.dpu

Consequences of omitting relevant inputs on the quality of the data envelopment analysis under different input correlation structures

This paper establishes the consequences of a wrong specification on the quality of the data envelopment analysis. Specifically, the case of omitting a relevant variable in the input oriented problem is analyzed when there are different correlation structures between the inputs. It is established that the correlation matrix gives relevant information about the homogeneity of the decision making units and the intensity of inputs used in the production process. The methodology is based on a series of Monte Carlo simulations and the quality of the data envelopment analysis is measured as the difference between the true efficiency and the efficiency calculated. It is found that omitting relevant inputs causes inconsistency, and this problem is worse when there is a negative correlation structure.This paper establishes the consequences of a wrong specification on the quality of the data envelopment analysis. Specifically, the case of omitting a relevant variable in the input oriented problem is analyzed when there are different correlation structures between the inputs. It is established that the correlation matrix gives relevant information about the homogeneity of the decision making units and the intensity of inputs used in the production process. The methodology is based on a series of Monte Carlo simulations and the quality of the data envelopment analysis is measured as the difference between the true efficiency and the efficiency calculated. It is found that omitting relevant inputs causes inconsistency, and this problem is worse when there is a negative correlation structure

Cross-selling in Colombian pension funds: An approach using survival analysis

El desarrollo de estrategias comerciales para realizar ventas cruzadas efectivas de servicios pensionales, puede ser uno de los retos más grandes de los fondos de pensiones. Se utilizó la base de datos de los afiliados a un fondo de pensiones obligatorias colombiano para implementar varios modelos que describen la incidencia de 4 características propias de los afiliados, sobre la probabilidad de ingresar al fondo de pensiones voluntarias en el siguiente mes. Los modelos se fundamentan en las técnicas de análisis de supervivencia.The development of commercial strategies for effective cross-sell pension services may be one of the biggest challenges of pension funds. The database of the affiliates of a Colombian mandatory pension fund was used to implement several models that describe the incidence of 4 characteristics of affiliates on the probability of entering the voluntary pension fund in the following month. The models are based on the survival analysis techniques

La volatilidad de la tasa de interés a corto plazo: un ejercicio para la economía colombiana, 2001-2006

Este artículo analiza diversas metodologías para la modelación de la volatilidad de la tasa de interés a corto plazo. Específicamente se analizarán los resultados que se obtienen a través de la especificación CKLS, heterocedasticidad condicionada y mixta. Los hechos estilizados enseñan que la mejor especificación para describir el proceso generador de la tasa de interés interbancaria en la economía colombiana para el período 2001-2006 es el modelo EGARCH. Se encuentra que las innovaciones positivas en la tasa de interés ocasionan una volatilidad 22,3% mayor que innovaciones negativas de la misma magnitud. Además, el proceso converge a una media no condicionada de 7,11% con una corrección diaria del 1,2%. Se encuentra que el modelo ofrece pronósticos relativamente sensatos a un plazo de tres meses

La volatilidad de la tasa de interés a corto plazo: Un ejercicio para la economía Colombiana, 2001–2006

Este artículo analiza diversas metodologías para la modelación de la volatilidad de la tasa de interés a corto plazo. Específicamente se analizarán los resultados que se obtienen a través de la especificación CKLS, Heterocedasticidad Condicionada y Mixta. Los hechos estilizados enseñan que la mejor especificación para describir el proceso generador de la tasa de interés interbancaria en la economía colombiana para el período 2001–2006 es el modelo EGARCH. Se encuentra que las innovaciones positivas en la tasa de interés ocasionan una volatilidad 22,3% mayor que innovaciones negativas de la misma magnitud. Además, el proceso converge a una media no condicionada de 7,11% con una corrección diaria del 1,2%. Se encuentra que el modelo ofrece pronósticos relativamente sensatos a un plazo de tres meses.In this paper we analyze different methodologies that are used to handle the short term interest rate volatility. Specifically, we shall analyze the outcomes that are obtained through three specifications: CKLS, Conditional Heteroscedastic and BHK. The evidence shows that the better specification is reached through the EGARCH model. It is found that positive shocks in the short term interest rate cause a volatility 22,3% higher than negative shock of the same size. Also, the process converges to an unconditioned mean of 7,11% with a correction factor of 1,2% daily. It is found that the model offers good forecast in a period of three months

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

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