Efficient rank tests for semiparametric competing risk models

We consider a semiparametric competing risk model given by k independent survival times. The paper offers an asymptotic treatment of tests for the semiparametric null hypothesis of equality of the underlying risks. It turns out that modified rank tests are asymptotically efficient for certain semiparametric submodels, where the baseline hazard is a nuisance parameter. In addition, the asymptotic relative efficiency of the present tests is derived. A comparison of asymptotic power functions can then be used to classify various tests proposed earlier in the literature. For instance a chi-square type test is efficient for proportional hazards. Data driven tests of likelihood ratio type are proposed for cones of alternatives. We will consider certain stochastically increasing alternatives as a special example. The paper shows how the concept of local asymptotic normality of Le Cam works for hazard oriented models.     

The association between two random elements: A complete characterization and odds ratio models

For random elements X and Y (e.g. vectors) a complete characterization of their association is given in terms of an odds ratio function. The main result establishes for any odds ratio function and any pre-specified marginals the unique existence of a corresponding joint distribution (the joint density is obtained as a limit of an iterative procedure of marginal fittings). Restricting only the odds ratio function but not the marginals leads to semi-parmetric association models for which statistical inference is available for samples drawn conditionally on either X or Y. Log-bilinear association models for random vectors X and Y are introduced which generalize standard (regression) models by removing restrictions on the marginals. In particular, the logistic regression model is recognized as a log-bilinear association model. And the joint distribution of X and Y is shown to be multivariate normal if and only if both marginals are normal and the association is log-bilinear.Acknowledgements The author thanks both referees for their helpful comments which improved the first draft of the paper.     

Learning-by-doing versus Schooling in a Model of Endogenous Growth

A two sector model of learning-by-doing measured by means of production aggregated over time and of human capital accumulation in a schooling sector is presented. Time utilization is rival between schooling and learning-by-doing. Depending on the sum of elasticities of the accumulated factors (i.e., of production experience and educational human capital) in both sectors, a situation with or without endogenous growth results. Dynamic optimization of the choice between leisure and working and of the division of human capital between education and production is executed. Transitional dynamics are analyzed for a Cobb-Douglas example and a numerical simulation is performed.JEL classification: C61, D90, O41.Acknowledgements The author would like to thank Eric C. Meyer and two anonymous referees for helpful comments. The usual caveats apply.revised version received November 23, 2003     

Possible economic impacts of a shutdown of the thermohaline circulation: an application of <Emphasis Type="Italic">FUND</Emphasis>

Climate change can lead to a substantial reduction of the strength of the thermohaline circulation in the world oceans. This is often thought to have severe consequences particularly on the North Atlantic region and Northern and Western Europe. The integrated assessment model FUND is used to estimate the extent of these impacts. The results indicate that, owing to a slower warming (rather than cooling) of the regions most affected by a thermohaline circulation collapse, climate change induced damages in these regions would be smaller in case of a shutdown of the thermohaline circulation. However, even with a thermohaline circulation collapse, the total and marginal impacts of climate change are negative.JEL Classification: Q510, Q540We are grateful to Till Kuhlbrodt for providing the CLIMBER data and to Andre Krebber for processing them. The German Federal Ministry for Education and Research through the INTEGRATION project, the US National Science Foundation through the Center for Integrated Study of the Human Dimensions of Global Change (SBR-9521914) and the Michael Otto Foundation provided welcome financial support.     

Trust and economic growth: a robustness analysis

This paper analyses the robustness of results on the relationshipbetween growth and trust previously derived by Knack and Keefer(1997) and Zak and Knack (2001) along several dimensions, acknowledgingthe complexity of the concept of robustness. Our results showthat the Knack and Keefer results are only limitedly robust,whereas the results found by Zak and Knack are highly robustin terms of significance of the estimated coefficients and reasonablyrobust in terms of the estimated effect size. The improvementin robustness is caused by the inclusion of countries with relativelylow scores on trust (most notably, the Philippines and Peru).Overall, our results point at a relatively important role fortrust. However, the answer to the question how large this payoffactually is depends on the set of conditioning variables controlledfor in the regression analysis and—to an even larger extent—onthe underlying sample.     

Managers can drive their subordinates mad

This article explores the phenomenon of "folie à deux"--an aberrant relationship between manager and subordinates that is characterized by shared delusions. Though most visible among public figures like Adolf Hitler, J. Edgar Hoover and Jim Jones, the problem also surfaces among private managers and their associates with dangerous implications for the firm. In folie à deux, the unusual behavior patterns of a manager in an isolated setting become mirrored by dependent subordinates, and the organization loses touch with its original goals and strategies. The author describes the dynamics of this phenomenon and details steps to remedy the situation. Once recognized, he suggests that the manager establish a trusting relationship with the instigator as a prelude to altering the behavior patterns, then transfer the subordinates and reorient the work climate so that independence and responsibility are encouraged. If the instigator is a powerful executive, the author suggests enlisting the support of a countervailing force, such as the government or a union, to guide the organization away from possible self-destructive adventures.     

On the (nonlinear) relationship between exchange rate uncertainty and trade — An investigation of US trade figures in the group of seven

In this paper bilateral models formalizing monthly growth of US imports and exports are employed to investigate the potential of nonlinear relationships linking exchange rate uncertainty and trade growth. Parametric linear and nonlinear as well as semiparametric time series models are evaluated in terms of fitting and ex ante forecasting. The overall impact of exchange rate variations on trade growth is found to be weak. In periods of large exchange rate variations, trade growth forecasts gain from conditioning on volatility. Empirical results support the view that the relationship of interest might be non-linear and, moreover, lacks homogeneity across countries and imports vs. exports. JEL no. C14, C22, F31, F41     

Der prognostische Gehalt der Nachrichtenwert-Theorie

In this article, news value theory is reformulated in a way that allows for predicting the length of news stories by the news value of news factors, and by the news factors of single stories. From a part of a sample, the news value of news factors is determined, and the expected length of stories is calculated for another part of the sample. Calculated length is then compared with measured length. There is a correlation of r =.54 between theoretical and empirical values. Theoretical and methodological conclusions are drawn from the results of the various analytic steps.     

领先财富管理的运营思路——BCG中国财富管理市场研究报告摘要

波士顿咨询公司(BCG)发布的有关中国财富管理市场的最新报告探讨了在中国建立领先的财富管理业务的关键因素.BCG授权本刊撷取其精要,希望能给予致力于提升中国财富管理水平的机构和理财从业人员有益的启示.