Efficiency and Productivity in the Spanish Food Distribution Sector

This study investigated the efficiency and productivity change of a sample of food distribution units (MERCAs) in Spain over the 1.997-1.999 period, applying non-parametric frontier methodology in a sales efficiency framework. We specified a mean sales model composed of two blocks of variables, the production block, and the marketing management block. Then we applied output oriented DEA methodology to perform the efficiency analysis, also taking into account the overall efficiency decomposition into pure and scale efficiency. The Malmquist index was calculated in order to analyse the components of the productivity change. The mean pure sales efficiency index was high, around 0.8, the mean scale index being 0,9. As appears from the results, six food distribution units were efficient, but some of the wholesale markets need to adapt their sales technology in order that their input bundle reaches a Most Productive Scale Size unit. We found no evidence of technical change during the period considered, but concluded that a notable scale efficiency change took place during the studied period. To summarise, we conclude that improvement in sales efficiency could be reached in the studied sector in both the pure and the scale efficiency.Efficiency, Productivity, DEA method, Malmquist index, Food Distribution Unit, Productivity Analysis,

The linear model without a constant term and the coefficient of determination. A Monte Carlo study

En el presente trabajo se analiza y compara mediante un experimento Monte Carlo el comportamiento de cinco expresiones para el Coeficiente de Determinación cuando el modelo lineal se especifica sin término independiente. Se ensayan distintos valores del parámetro poblacional P2, que mide la proporción de varianza explicada por el modelo, introduciendo también la multicolinealidad como factor de variación en el diseño. Se confirma el coeficiente propuesto por Heijmans y Neudecker (1987) y el de Barten (1987), como idóneos para medir la bondad del modelo

El Análisis de Eficiencia en el Sector Público mediante Métodos Frontera

En este trabajo se presenta la metodología que resuelve el análisis de eficiencia mediante métodos frontera. Se desarrollan los objetivos generales de dicho análisis y se exponen las dos técnicas más utilizadas en el mundo de la economía aplicada. En el ámbito no paramétrico el método más aplicado recibe el nombre de Data Envelopment Análisis (DEA), y estima la frontera de producción mediante la envolvente de los datos de la muestra analizada, utilizando técnicas de programación matemática. El método paramétrico estima una función frontera de producción de carácter econométrico. La distancia a la frontera permite determinar el índice de eficiencia por cualquiera de los dos métodos. Igualmente se exponen las características del análisis de eficiencia aplicado al sector público particularizando para cada uno de los subsectores más estudiados como son el sector sanitario, el de educación secundaria, la docencia e investigación en la universidad, y los municipios. Las técnicas de análisis de eficiencia mediante función frontera se presentan como idóneas para ser aplicadas al sector publico, a pesar de las dificultades inherentes en dicho sector y además se aconseja la aplicación de las mismas con objeto de detectar debilidades en el sistema y plantear estrategias encaminadas a incrementar el nivel de eficiencia del mismo

A Strategy for Testing the Unit Root in AR(1) Model with Intercept. A Monte Carlo Experiment

In this paper we introduce a strategy for testing the unit root hypothesis in a first-order autoregressive process with an unknown intercept where the initial value of the variable is a known constant. In the context of this model the standard Dickey-Fuller test is nonsimilar, the intercept being the nuisance parameter. The testing strategy we propose takes into account this non-similarity. It is an unusual two-sided test of the random walk hypothesis since it involves two distributions where the acceptance region is constructed by taking away equal areas for the lower tail of the Student’s t distribution and the upper tail of the distribution tabulated by Dickey and Fuller under the null hypothesis of unit root. In some cases, this strategy does not allow the taking of a direct decision concerning the existence of a unit root. To deal with these situations we suggest testing for the significance of the intercept, and if doubt continues, we use F1 test proposed by Dickey and Fuller (1981). Finally, in order to demonstrate the relevance of non-similarity, Monte Carlo simulations are used to show that the testing strategy is more powerful at stable alternatives and has less size distortions than the two-sided test considered by Dickey and Fuller.unit root, Dickey-Fuller tests, non-similarity, Monte Carlo simulations, empirical size, nominal size

A spreading method to improve efficiency prediction.

In efficiency analysis by means of a stochastic frontier production function, the composite error variable includes the inefficiency component. For this reason, individual prediction cannot be made directly from an estimation of the error in the model. In order to solve this problem, Jondrow et al (1982), and Battese and Coelli (1988) separately developed two different procedures, based on the expectation operator of the conditional distributions. Although the two predictors are different, each suffers from a shrinkage effect with respect to the distribution of theoretical efficiency. Our study of the behaviour of these two predictors leads us to conclude that the value of the gamma parameter has a great influence on the above-mentioned effect, producing a truncation of the distribution that could be more than 50%, so that the extreme values of the efficiency can never be estimated by the predictors considered. We also propose a method that spreads out the predicted efficiencies in order to minimise the shrinkage effect. The Monte Carlo results demonstrate that the corrected predictions have a better behaviour than the original predictors.Efficiency, Frontier models, Monte Carlo methods.

Law of one price in the Spanish olive oil market

El objetivo de este trabajo es el estudio de la integración del mercado español del aceite de oliva y la contrastación de la Ley de Precio Único (LPU) en dicho mercado. El análisis se lleva a cabo aplicando la técnica multivariante de cointegración a series mensuales (1987-2001) de precios de aceite de oliva correspondientes a las regiones en que el MAPA divide el mercado español peninsular. Los resultados muestran que los mercados españoles de aceite de oliva tienen un alto grado de integración siendo Noreste el mercado líder. No obstante, el mecanismo de transmisión de precios no es perfecto.The aim of this paper is the study of long-run market integration of olive oil in Spain and the testing of the Law of One Price (LOP) in this market. The study is carried out using multivariate cointegration methodology and applied to monthly data on olive oil prices in Spain (1987-2001) corresponding to the regions considered by the Spanish Ministry of Agriculture, Fisheries and Food. The results show that Spanish olive oil markets are highly integrated with the Northeast being the leading market. However, perfect integration cannot be accepte

Contrastación de la ley de precio único en el mercado español del aceite de oliva

En este trabajo se contrasta la eficiencia del mercado español del aceite de oliva puro a través del cumplimiento de la Ley de Precio Unico (LPU), considerando las zonas de consumo que, para este producto, define el MAPA. El análisis se lleva a cabo desde la perspectiva de la teoría de la cointegración, contrastando la LPU a largo plazo mediante el procedimiento propuesto por Johansen. Los resultados indican la existencia de tres relaciones de cointegración entre las series de precios analizadas, aunque no evidencian el cumplimento de la LPU. Los constrastes de exogeneidad débil revelan que Andalucía y Noreste pueden ser considerados como mercados líderes.market integration, Law of One Price, olive oil, unit root, co-integration, weak exogeneity

Estudio económico de las explotaciones de regadío de la zona "El Saltador" de Huércal-Overa (Almería)

Este trabajo recoge los resultados de un estudio económico de las explotaciones de la zona de Transformación en Riego y Colonización de "El Saltador", Comarca de Huércal-Overa (Almería). Se investiga sobre las posibles causas del abandono de las mismas, realizando un estudio de la realidad socioeconómica de dichas explotaciones y un análisis económico del agua de riego. Se detecta además del abandono de la actividad agraria en esta zona de regadío, un alto grado de infrautilización de la SAU (Superficie Agrícola Útil). Todo ello obedece fundamentalmente a razones tanto de la estructura de la producción como de la comercialización, que se traducen en una baja productividad media de la tierra, el trabajo y el agua. Se propone mejorar el sistema de riego y establecer una labor de extensión enfocada a conseguir un mejor uso del agua y del abonado, y potenciar la comercialización

Efficiency and productivity in the Spanish food distribution sector

This study investigated the efficiency and productivity change of a sample of food distribution units (MERCAs) in Spain over the 1.997-1.999 period, applying non-parametric frontier methodology in a sales efficiency framework. We specified a mean sales model composed of two blocks of variables, the production block, and the marketing management block. Then we applied output oriented DEA methodology to perform the efficiency analysis, also taking into account the overall efficiency decomposition into pure and scale efficiency. The Malmquist index was calculated in order to analyse the components of the productivity change. The mean pure sales efficiency index was high, around 0.8, the mean scale index being 0,9. As appears from the results, six food distribution units were efficient, but some of the wholesale markets need to adapt their sales technology in order that their input bundle reaches a Most Productive Scale Size unit. We found no evidence of technical change during the period considered, but concluded that a notable scale efficiency change took place during the studied period. To summarise, we conclude that improvement in sales efficiency could be reached in the studied sector in both the pure and the scale efficiency

Analysis on the individual efficiency prediction in the composed error frontier model. A Monte Carlo study

This study seeks to analyse some important questions related to the Stochastic Frontier Model, such as the method proposed by Jondrow et al (1982) to separate the error term into its two components, and the measure of efficiency given by Timmer (1971). To this purpose, a Monte Carlo experiment has been carried out using the Half-Normal and Normal-Exponential specifications throughout the rank of the γ parameter. The estimation errors have been eliminated, so that the intrinsic variability of the conditional of u given ε can be evaluated. In addition, the behaviour of the mean and mode as point estimators of u is investigated. The results have yielded some interesting findings. We have observed that both the point estimates and the mean efficiency are more precise in cases of lower efficiency. This occurs when the variable that generates the inefficiency outweights the one that picks up the errors out of the control. The change in order found between the estimated efficiency and its estimated value is misleadingly high especially for low ε, which underlines the risk of estimating at these values