Estimation of Asymmetric Stochastic Volatility Models: Application to Daily Average Prices of Energy Products

Energy supply and demand, and as a consequence energy prices, are likely to represent one of the biggest challenges of the 21st century. Commodity markets exhibit increased volatility when there is little or no underutilized supply capability to meet natural fluctuations in demand. In the case of energy markets, the large capital requirements and significant lead times associated with energy production and delivery make them more susceptible to the imbalances in supply capability and demand. Energy price volatility has destructive impact on market agents, and this impact is intensified when the prices exhibit asymmetric volatility. This article pursues two aspects of the issue. First we consider general aspects, especially the asymmetric pattern of volatility of daily returns of different types of energy products. Then, we analyze the behaviour of daily returns by using traditional models of volatility that include AGARCH, TGARCH, EGARCH, and ARSV strategies, as well as a threshold asymmetric autoregressive stochastic volatility (TA-ARSV) model that we propose. The energy products considered in this analysis are probably the most relevant energy products for the economic activity of the nations and the economic relations between countries: Crude Oil (OPEC reference basket and London Brent index), Gasoline, Natural Gas, Butane, and Propane. We use spot prices and the time reference ranges from 1986–1993 to 2009 depending on the product.     

Trade‐led growth hypothesis in Cuban commercial regimes since 19601,2

This study examines the impact of trade on Cuban growth during different commercial policy regimes spanning the period from 1960 up to 2004, encompassing two essential economic structural transformations: the Cuban revolution and the fall of the Berlin Wall. For this purpose, the Granger causality is used by means of the modified Wald test for augmented‐level vector autoregressive model with integrated and cointegrated processes introduced by Toda and Yamamoto (1995) and Dolado and Lutekepohl (1996) . We show an import‐led growth hypothesis during the Soviet‐oriented pattern that is rejected after 1990, when exports are not only responsive to growth expansion but also to imports’ behaviour.     

Repeated Dichotomous Choice Formats for Elicitation of Willingness to Pay: Simultaneous Estimation and Anchoring Effect

Repeated dichotomous choice contingent valuation data are generated from responses to a succession of binary questions regarding alternative prices for an environmental good. In this paper we propose a simultaneous equation model that allows for endogeneity and error correlation across the responses at each stage of the bidding process. The model allows us to study the evolution of anchoring effects after the second dichotomous choice question. Estimation involves the Bayesian techniques of Gibbs sampling and data augmentation, and the application focuses on the preservation value of a natural area. The results for a data set involving up to four successive dichotomous choice questions show that restricted multiple-bounded models are rejected by the data with the general model. In addition, willingness to pay tends to stabilize after the second stage in the elicitation process for the general unrestricted model. When taking anchoring effects into consideration, it is revealed that individuals’ responses in the latter stages are influenced by the sequence of bid prices offered in earlier questions. Nevertheless, they do not have a significant effect on welfare estimates.      

Influence measures on profile analysis with elliptical data through Frèchet’s metric

In this paper, from Frèchet’s metric, diagnostic tools are constructed for the detection of influential observations in Profile Analysis with elliptically distributed random errors . This distributional hypothesis allows the application of the proposed diagnostics to a wide variety of random experiences, not only for data from a multivariate normal distribution but also from other symmetric distributions, commonly used in studies of several sciences. The diagnostics are based on Frèchet’s distance between the distributions of the basic statistics in Profile Analysis, in the postulated model and in the perturbed model obtained by deleting an observation from the sample data. This metric is highly useful since it enables the analysis of the influence on the point estimation and the estimation error. Applications on two data sets are provided.     

农民参与新型农村合作医疗的意愿及影响因素分析——基于河北省唐山、保定、沧州三地的调查

对河北省409户农户问卷调查分析显示，虽然大多数农民已经参合，但是农民对合作医疗的知晓度、合作医疗制度的报销比例、参合点的药价水平以及农民本身的健康状况等都会影响农民的参合意愿，进而影响合作医疗制度的可持续发展。     

The Effectiveness and Efficiency of Active Labour Market Policies in Poland

Following the predominance of macroeconomic stabilisation policies and passive income support schemes in the first phase of transition, active labour market policies (ALMPs) have now come to play a more important role in transition economies. This paper looks at the Polish experience and provides empirical evidence on the effectiveness of ALMPs. We use the Polish Labour Force Survey of August 1994 in combination with its Supplement on the Evaluation of Labour Market Policies together with data on ALMP expenditure at the regional (voivodship) level. The macroeconometric analysis of the relationship between labour market flows and ALMP expenditure shows no significant effects. The microeconometric analysis reveals that ALMPs are not particularly well targeted at the problem groups in the labour market. That is, women and people with basic vocational education do not receive enough attention. As to the effectiveness of ALMPs, the paper shows that former participants cannot expect to find employment more easily than their peers who have been unemployed but have not been in a programme. Subjective evaluations of former participants also suggest that ALMPs, but especially works programmes, have not improved their chances to find a job. This revised version was published online in July 2006 with corrections to the Cover Date.     

An Examination of the Quality of Jobs in the Call Center Industry

This paper examines jobs in the information society and the new economy, taking as its focus the call center industry. More specifically, the study analyzes the degree of variability of the quality of call center jobs. In order to achieve this objective, an index of job quality is generated, and an empirical analysis of the characteristics of jobs in call centers is carried out. This allows us to determine the level and variability of quality of jobs in this sector and to establish whether the reality of these jobs is as good as the forecasts for work in the new economy.