Tests of Hypotheses Arising In the Correlated Random Coefficient Model

This paper examines the correlated random coefficient model. It extends the analysis of Swamy (1971), who pioneered the uncorrelated random coefficient model in economics. We develop the properties of the correlated random coefficient model and derive a new representation of the variance of the instrumental variable estimator for that model. We develop tests of the validity of the correlated random coefficient model against the null hypothesis of the uncorrelated random coefficient model.     

The effect of pay-for-performance contracts on wages

I investigate the role played by learning and self-selection according to comparative advantage in the often reported result that piece rate workers (including commissions) earn more on average compared to other workers. With comparative advantage, the returns to skills differ across pay methods. I find that comparative advantage along with learning about worker skills seem to play a role for workers who are either at an early stage in their career or who are observed for the first time in a given job-match. For older workers, the return to skills is basically the same across pay methods.     

Short Run Constraints and the Increasing Marginal Value of Time in Recreation

Leisure activities such as local recreation trips usually take place in discrete blocks of time that are surrounded by time devoted to other commitments. It can be costly to transfer time between blocks to allow for longer outings. These observations affect the value of time within those blocks and suggest that traditional methods for valuing time using labor markets miss important considerations. This paper presents a new model for time valuation that uses non-employment time commitments to infer the shadow value of time spent in recreation. A unique survey that elicited revealed and stated preference data on household time allocation is used to implement the model. The results support the conclusion that there is an increasing marginal value of time for recreation as the trip length increases.     

Understanding perpetual R&D races

This paper presents an experimental study of dynamic indefinite horizon R&D races with uncertainty and multiple prizes. The theoretical predictions are highly sensitive: small parameter changes determine if we should expect technological competition, and if so whether it is sustained, or if the market converges into one with entrenched leadership and lower aggregate R&D. The subjects’ strategies are far less sensitive. In most of the treatments, the R&D races tend to converge to entrenched leadership. We propose and apply a quantal response extension of Markov perfection that is qualitatively and largely quantitatively consistent with the experimental observations.     

Understanding forecast failure of ESTAR models of real exchange rates

The forecast performance of the empirical ESTAR model of Taylor et al. (2001) is examined for 4 bilateral real exchange rate series over an out-of-sample evaluation period of nearly 12?years. Point as well as density forecasts are constructed, considering forecast horizons of 1 to 22 steps head. The study finds that no forecast gains over a simple AR(1) specification exist at any of the forecast horizons that are considered, regardless of whether point or density forecasts are utilised in the evaluation. Non-parametric methods are used in conjunction with simulation techniques to learn about the models and their forecasts. It is shown graphically that the nonlinearity in the conditional means (or point forecasts) of the ESTAR model decreases as the forecast horizon increases. The non-parametric methods show also that the multiple steps ahead forecast densities are normal looking with no signs of bi-modality, skewness or kurtosis.     

Wage inequality in a developing country: decrease in minimum wage or increase in education returns

In this paper we analyze the increase in wage inequality observed in the Uruguayan labour market during the last decade, by studying how the changes in minimum wage and returns to education affected the wage structure. Although in most developed countries a significant proportion of the increase in wage inequality is explained by a fall in the real minimum wage, this is not the case for the Uruguayan labour market. We observe that returns to education increased significantly, which could explain the increase of wage dispersion by its effects on the upper tail of the wage distribution. To derive these conclusions we follow a parametric and nonparametric quantile regression approach.     

Multidimensionales Verfahren zur Bestimmung des Regelleistungsbedarfes unter Berücksichtigung von Unsicherheiten

One of the most crucial constraints in operation of electrical power supply systems is the permanent balance between generation and load. Reserve power is held ready to be able to keep this balance also in case of the occurrence of unpredictable events like power plant outages or inevitable deviations of power injections from their predicted values. At this, the allocation of operating reserves is in the field of conflict between level of reliability and cost effectiveness. The amount of reserve generation capacity required in a control area heavily depends on prediction quality which constitutes the need for high quality predictions. This article is about the influence of prediction quality on the amount of reserve generation capacity required in a control area. The algorithms for the assessment of required reserve generation capacity known from literature use the variation calculus technique to account for the aforementioned unpredictable events and prediction errors. In this article, an extension to a convolution-based method is presented in which the uncertainties of the predictions are expressed using intervals. Each parameter is represented by an independent dimension, assuming statistical independence among them. This allows the distinct analysis of each parameter’s influence on the amount of required reserve generation capacity. In addition, two methods for the visualization of the multi-dimensional results are presented, allowing a comprehensive analysis of the parameters’ influences. Standard distribution functions are used to represent the parameters for the simulation and the results are shown as probability density functions of possible imbalances. Based on forecasts of the development of conventional power plants and regenerative generation in the years 2020, 2030 and 2040, the required control power of the future German transmission system is calculated. Influences and dependencies are identified with the extended convolution-based method.     

Directional duality theory Directional duality theory

In this paper we introduce a complete duality theory based on directional distance functions. This duality theory parallels the duality theory based on radial distance functions in Färe and Primont (1995).     

风险管理，你犯错了吗？

我们无法预测“黑天鹅事件”的发生,与其一味幻想可以执掌未来,防堵风险,不如设法降低此类威胁带来的不良影响。     

A geometric approach to disequilibrium exchange rate fluctuations: The case of Switzerland

This article deals with the effects of exchange rate fluctuations in non-Walrasian macromodels. A demand driven model (‘Keynesian Unemployment’) and a supply driven model (‘Classical Unemployment’), both estimated on Swiss data, are alternatively considered. In each case an exchange rate modification and possible accompanying policy measures are considered. The feasible consequences on employment and the balance of trade are investigated by means of a geometric comparative static technique. For each type of fix-price equilibrium, the favourable conditions for a devaluation and a revaluation are thus emphasised.