Uninsured idiosyncratic risk, liquidity constraints and aggregate fluctuations

Summary. I study the role played by uninsured idiosyncratic risk and liquidity constraints in the propagation of aggregate fluctuations. To this purpose, I compare the aggregate fluctuations of two model economies that differ in their insurance technologies only. In one of these model economies liquidity constrained households vary their holdings of a nominally denominated asset in order to buffer an uninsured idiosyncratic shock to their individual production opportunities. In the other economy every idiosyncratic component of risk can be costlessly insured. I find that the limited insurance technology implies fluctuations in output that are 20% larger, fluctuations in hours relative to output that are 9% larger, fluctuations in consumption relative to output that are 18% smaller, and a correlation of hours and productivity that is 15% smaller than those that obtain under the full insurance technology. Received: March 6, 1996; revised version August 15, 1996     

A Comparison of χ2, RFA and IRT Based Procedures in the Detection of DIF

Bias research began at the end of the 1960s anddeveloped rapidly in the following decades for obvioussocial and political reasons, and due to the importantimpact that this issue has on the field ofpsychological and educational measurement. Since then,several methods have been proposed for the study anddetection of item bias or differential itemfunctioning (DIF). This paper presents a simulationstudy comparing the potential of some of these methodsfor detecting DIF: two IRT-based techniques (area measures), three ²-based procedures (MantelHaenszel, Logit Model and Logistic Regression) and theRestricted Factor Analysis method. The results showthat the technique that appears to do the best job isthe Mantel Haenszel statistic. Moreover, all detectiontechniques tend to overidentify DIF items, that is,some of the items labeled with DIF may in fact bewithout DIF. This tendency is slightly reversed in theLogistic Regression procedure.     

An Approach to Support Negotiation Processes with Imprecise Information Multicriteria Additive Models

This paper discusses the possible uses of the VIP (Variable Interdependent Parameters) Analysis software and methodology in negotiation support. VIP Analysis is a decision support tool that incorporates complementary approaches to deal with the aggregation of multi-criteria performances under imprecise information. Its purpose is to support the evaluation of a discrete set of alternatives according to multi-attribute additive value functions. We propose extensions of the methodology of VIP Analysis to address explicitly the differences among the actors in terms of the weights space.     

Fraud Detection Using a Multinomial Logit Model With Missing Information

Recently, Artís, Ayuso, and Guillén (2002, Journal of Risk and Insurance 69: 325–340; henceforth AAG) estimate a logit model using claims data. Some of the claims are categorized as “honest” and other claims are known to be fraudulent. Using the approach of Hausman, Abrevaya, and Scott‐Morton (1998 Journal of Econometrics 87: 239‐269), AAG estimate a modified logit model allowing for the possibility that some claims classified as honest might actually be fraudulent. Applying this model to data on Spanish automobile insurance claims, AGG find that 5 percent of the fraudulent claims go undetected. The purpose of this article is to estimate the model of AAG using a logit model with missing information. A constrained version of this model is used to reexamine the Spanish insurance claim data. The results indicate how to identify misclassified claims. We also show how misclassified claims can be identified using the AAG approach. We show that both approaches can be used to probabilistically identify misclassified claims.     

Monte Carlo Simulation Techniques in a Decision Support System for Group Decision Making

This paper describes a group decision support system based on an additive multi-attribute utility model for identifying a consensus strategy in group decision-making problems where several decision-makers or groups of decision-makers elicit their own preferences separately. On the one hand, the system provides procedures to quantify the DMs or group of DMs preferences separately. This involves assessing the DMs or group of DMs component utilities that represent their preferences regarding the respective possible attribute values and objective weights that represent the relative importance of the criteria. On the other hand, we propose Monte Carlo simulation techniques for identifying a consensus strategy. An iterative process will be carried out, where, after the simulations have been performed, the imprecise component utilities and weights corresponding to the different DMs or groups of DMs are tightened to output more meaningful information in the next simulations to achieve a consensus strategy. Finally, an application to the evaluation of remedial strategies for restoring contaminated aquatic ecosystems illustrates the usefulness and flexibility of this decision support tool.     

Economic Efficiency and Productivity Growth in the Post-Privatization Chilean Hydroelectric Industry

Chiles hydroelectric industry was privatized in 1985, but required to operate within a regulatory framework designed to achieve a competitive outcome. A centralized dispatch center was established to ensure production at minimum cost, subject to constraints on minimum release and minimum reservoir stock. A reluctance to rapidly reduce the industry work force may also have existed. We develop a constrained cost-minimization model for thermal and hydro generation to obtain the shadow price of water and to determine the qualitative effect of these constraints on allocative efficiency. Using panel data from 1986–1997, we assess the economic efficiency of the hydro industry by estimating a stochastic distance frontier and price equations from the dual cost-minimization problem. We find dramatic increases in technical change and productivity change, with positive efficiency change for all years but the last. We also observe a dramatic decline in allocative inefficiencies over our sample period. The share of hydro generation from run-of-river and thermal plants relative to reservoir plants has increased, presumably in reaction to the water release and reservoir stock constraints, reducing the relative over-utilization of capital to water from the pre-1985 regime. Further, the over-utilization of labor to capital and water has fallen over time. However, considerable allocative inefficiencies remain, consistent with our finding of industry-wide scale economies. Substantial cost savings would result if technical and allocative efficiency were eliminated.JEL Classification: L94, D24     

An empirical note about additive outliers and nonstationarity in Latin-American inflation series

This note shows the empirical dangers of the presence of large additive outliers when testing for unit roots using standard unit root statistics. Using recent proposed procedures applied to four Latin-American inflation series, I show that the unit root hypothesis cannot be rejected.Jel classification: C2, C3, C5I want to thank Pierre Perron for useful comments on a preliminary version of this paper. Helpful comments from an anonymous referee, and Yiagadeesen Samy are appreciated. I thank the Editor Baldev Raj for useful comments about the final structure of this paper. Finally, I also thank André Lucas for helpful suggestions concerning the use of his nice computer program Robust Inference Plus Estimation (RIPE).First revision received: August 2001/Final revision received: December 2002     

The world wide web in the food and beverage sector in Spain

Despite its potential, the World Wide Web is not yet a real or viable alternative for marketing channels in Spain. This research attempts to identify and evaluate the factors that contribute and facilitate the development of the Web as an environment for commercial activities in the food and beverage sector in Spain. Spanish consumers have traditionally shown little interest in all forms of distance buying and direct marketing. A range of factors may facilitate this development such as continuous growth in access to the Internet, continued evolution of computer technology, reductions in Internet connection tariffs, and communication speed. Consumers' income, the availability of information online, and the online consumption experience may also act as an impulse for commercial developments on the Web.     

Explaining the reduction in the gender wage gap during the 1990–94 economic recession in Spain

Many studies reveal that male-female wage differentials increase with the level of unemployment, suggesting that women are hurt by a recession more than men. However, the 1990–94 economic recession in Spain contributed to reduce the gender wage gap by almost 5 percentage points (from 83.94 percent in 1990 to 90.44 percent in 1994). This was mainly due to the relative increase in services industry employment, the activity where the gender wage gap is the lowest.     

Context Variables as Cognitive Effort Modulators in Decision Making Using an Alternative-Based Processing Strategy

This paper examines how a number of decision context variables affect the cognitive effort required for decision making on dichotomical choice tasks. Subjects are trained in the use of a strategy in which information processing is alternative-based. The correlation between the attributes of the alternatives and the mean and variance of the difference between the attributes is manipulated. The results show that the effort needed for decision making increases as the mean of the differences decreases. Yet, neither the variance of the differences nor the correlation context affect the decision making effort in this type of strategies.