On the role of labor supply for the optimal size of Social Security

The paper studies the welfare effects of a Social Security system in a stylized overlapping generations economy with random production and capital accumulation. Different welfare concepts including long run optimality, social optimality, and time consistency are employed to determine the optimal size of the system. When labor supply is exogenous, a unique contribution level can be identified which is optimal according to all three concepts. When labor supply is endogenous, however, this result generically fails to hold and the long-run optimal solution is only constrained socially optimal while the time-consistent policy may even lead to an inefficient equilibrium.     

A consistent estimator for nonlinear regression models

In this paper an estimator for the general (nonlinear) regression model with random regressors is studied which is based on the Fourier transform of a certain weight function. Consistency and asymptotic normality of the estimator are established and simulation results are presented to illustrate the theoretical ones.Supported by the Hungarian National Science Foundation OTKA under Grants No. F 032060/2000 and F 046061/2004 and by the Bolyai Grant of the Hungarian Academy of Sciences.Received October 2003     

A note on a specification test of independence

In a recent paper Zheng (1997a) proposed a new specification test of independence between two random vectors by the kernel method. He showed asymptotic normality under the hypothesis and local alternatives. The present work investigates the asymptotic distribution of the corresponding test statistic under fixed alternatives. In this case asymptotic normality of a standardized statistic is still valid but with a different rate of convergence. Received: January 1999     

An ‘oil’igopoly theory of exploration

This paper develops a theory of ‘oil’igopoly exploration of an exhaustible resource. Strategic exploration and production are jointly derived in a three period subgame perfect equilibrium. While the ‘oil’igopoly theory of exploration shares many features with non-strategic models of exploration and production, there is one important difference. The ‘oil’igopoly theory of exploration predicts that firms who exhaust their proved reserves before they can convert their unproved reserves into proved reserves have an incentive to over-explore, relative to the Nash equilibrium level of exploration. A simple empirical prediction is that firms holding smaller proved reserves should be observed doing more exploration. This prediction is consistent with country-level production and reserve data in the post-World War II era.     

Response Effects in Surveys on Children and Adolescents: The Effect of Number of Response Options,Negative Wording,and Neutral Mid-Point

Social researchers increasingly survey children and young adolescents.They are convinced that information about perspectives, attitudes, and behaviors of childrenshould be collected from the children themselves. Methodological expertise on surveying childrenis still scarce, and researchers rely on ad-hoc knowledge from fields such as child psychiatry and educationaltesting, or on methodological knowledge on surveying adults. Regarding adults, empirical evidenceshows that respondent characteristics (cognitive abilities) as well asquestion characteristics (question difficulty) affect response quality.This study reports on a methodological survey experiment on theeffect of negatively formulated questions, the number of response options and offeringa neutral midpoint as response option question characteristics on the reliability of theresponses, using children and young adolescents as respondents.The study shows no effects of negatively formulated questions onthe reliability measures, although children respond consistently differently on negativelyformulated questions than on positively formulated questions. Taking all results on the effectsof number of response options and offering a neutral midpoints on the different reliabilitymeasures into consideration; it would appear that offering about four responseoptions is optimal with children as respondents.     

Asymptotic properties of estimators for the volume fractions of jointly stationary random sets

In the present paper, we show how a consistent estimator can be derived for the asymptotic covariance matrix of stationary 0–1-valued vector fields in R ^d , whose supports are jointly stationary random closed sets. As an example, which is of particular interest for statistical applications, we consider jointly stationary random closed sets associated with the Boolean model in R ^d such that the components indicate the frequency of coverage by the single grains of the Boolean model. For this model, a representation formula for the entries of the covariance matrix is obtained.     

Optimal policy in Markov-switching rational expectations models

In this paper we consider the optimal quadratic control problem of Markov-switching linear rational expectation models. These models are general and flexible tools for modelling not only regime but also model or parameter uncertainty. We show, first, how to find the solution of a Markov-switching linear rational expectation model. Based on this solution we then show how to apply dynamic programming to find the optimal time-consistent policy and the resulting Nash-Stackelberg equilibrium. Suitable modifications of the algorithm allow to deal with the (non-RE) case in which the policymaker and the private sector hold different beliefs or probabilities over regime change. We also show how the optimisation procedure can be employed to obtain the optimal policy under commitment. As an illustration we compute the optimal policy in a small open economy subject to stochastic structural breaks in some of its key parameters.     

时间一致性问题及其政策意义

传统的经济学理论认为熏相机抉择机制能有效地解决经济活动中的滞胀问题熏然而芬恩·基德兰德(FinnE.Kydland)和爱德华·普雷斯科特(EdwardC.Prescott)认为熏相机抉择机制所导致的只是一种次优的选择,政府只有采取一致性的货币或时间政策熏才能取得既定的经济目标熏达到经济的最优均衡。     

On the optimal size of Social Security in the presence of a stock market

The paper develops a stylized overlapping generations economy with random production and a stock market. The impact of a Social Security system on production, asset markets, and consumer welfare is analyzed. It is shown that any reduction in the contribution rate fosters capital accumulation and increases asset prices, wages, and production output. Different welfare criteria are applied to determine the optimal size of Social Security. It is shown that there exists a unique contribution rate which is long-run optimal, socially optimal, and time-consistent in the sense that no generation has an incentive to change it.     

不完备决策系统中发现偏好概率规则的粗糙集方法

为了从有偏好信息但信息不完全的多属性决策系统中获取概率决策规则,提出一种新的不完全信息的多属性粗糙决策分析方法。首先,提出扩展优势关系下相容度的概念;其次,基于相容度给出知识的粗糙近似,并证明了粗糙近似的基本性质;再次,给出粗糙近似的分类质量与β-约简的概念,并从不完全信息的偏好决策系统中导出概率决策规则;最后,通过一个实例说明新方法的可行性和有效性。