Clustering financial time series with variance ratio statistics

This study introduces a new distance measure for clustering financial time series based on variance ratio test statistics. The proposed metric attempts to assess the level of interdependence of time series from the point of view of return predictability. Simulation results show that this metric aggregates time series according to their serial dependence structure better than a metric based on the sample autocorrelations. An empirical application of this approach to international stock market returns is presented. The results suggest that this metric discriminates stock markets reasonably well according to size and the level of development. Furthermore, despite the substantial evolution of individual variance ratio statistics, the clustering pattern remains fairly stable across different time periods.     

Evaluating employee integrity: Moral and methodological problems

This paper reviews the research on proprietary paper and pencial tests of integrity or honesty, which have effectively supplanted polygraph examinations in evaluating the moral attributes of employees and applicants. Moral integrity is a complex issue that encompasses more than conventional notions of honesty and is difficult to operationalize as a psychological trait or construct. Integrity test questions are largely derived from polygraph interrogations and the tests validated through polygraph results. The field studies reviewed and an exploratory test cast doubt on the ability of these paper and pencil instruments to meet standards of construct validity. Other studies show promise of predictive validity in some situations. Unfortunately, the research designs used to substantiate the predictive powers of integrity tests failed to hold other workplace influences constant. In light of these findings, employers are urged to exercise caution in the use of these tests until further independent research is reported because of potential infringements on privacy and equal opportunity.     

将文化意识引入自考英语教学实践的初探

自考英语是我国成人高等教育中的一门重要课程。如何帮助英语基础较为薄弱的自考学生学好这门课程一直是个难点。笔者通过在教学实践中导入文化意识,力图优化课堂教学,为自考英语的教学作出有益的尝试。     

The great appreciation, the great depreciation, and the purchasing power parity hypothesis

Although there has been much recent work on purchasing power parity (PPP), neither univariate nor panel methods have produced strong rejections of unit roots in US dollar real exchange rates for industrialized countries during the post-1973 period. We investigate the hypothesis that these non-rejections can be explained by one episode, the large appreciation and depreciation of the dollar in the 1980s, by developing unit root tests which account for this event and maintain long-run PPP. Using panel methods, we can strongly reject the unit root null for those countries that adhere to the typical pattern of the dollar’s rise and fall.     

江浙沪三省市外商直接投资与环境污染的因果关系检验

文章利用1986-2003年江浙沪三省市实际利用外资额和废气排放量的数据进行了外商直接投资增长与环境污染加剧的因果关系检验,结果表明:在汇总的三省市数据和上海、江苏两省市的单独检验中,外商直接投资增长与环境污染加剧之间的因果关系较为明显;但是对于浙江省,这两者数据间的因果关系并不明显。建议今后一段时期内,长三角地区利用外资不仅要注重量的增加,更要注重质的提升,尤其是要提高外资利用的水平和效率,以缓解日益紧张的环境污染压力。     

Chi-Square Tests Under Models Close to the Normal Distribution

Many test statistics follow a χ² distribution because a normal model is assumed as underlying distribution. In this paper we obtain good analytic approximations for the p-value and the critical value of χ² tests when the underlying distribution is close but different from the normal model. With these approximations we study the robustness of validity of χ² tests     

我国货币政策传导的有效性——基于四种途径的实证分析

货币政策的传导渠道一般分为货币和信贷两大渠道。本文采用相关系数、单位根检验、协整理论和格兰杰因果检验对我国转轨经济下2000～2007年季度数据进行实证分析,结果表明货币渠道或信贷渠道不能独立对货币政策的传导发挥作用而是需要共同作用影响经济总产出,且相比而言货币渠道更为重要。在转轨经济下,短期完善信贷渠道长期规划货币渠道成为提高货币政策传导有效性的关键。     

Testing for hysteresis: Unemployment persistence and wage adjustment

This paper proposes a new testing strategy for unemployment hysteresis as the joint restriction of a unit-root in the unemployment rate and no feedback effect of unemployment in the Phillips wage equation. The associated test statistics are derived when this joint restriction is imposed and when a sequential two steps testing strategy is adopted. An empirical application leads to reject the null hypothesis of wage hysteresis for most of our OECD countries. Evidence against hysteresis is reinforced when accounting for wage adjustments in the bivariate approach. First version received: July 1999/Final version received: May 2002 RID="*" ID="*"  We thank R. Boyer, F. Collard, F. Karamé, F. Langot, F. Mihoubi, W. Pohlmeier and two anonymous referees for fruitful comments. This paper has also benefited from discussions at the T2M conference (Montréal, may 1999) and ESEM99 (Santiago, august 1999). The traditional disclaimer applies.     

Real estate returns,money and fiscal deficits: Is the real estate market efficient?

This research examines the causal relationship between several financial variables and a portfolio of real estate returns using monthly data from January 1965 to December 1986. The empirical analysis is based on multivariate Granger-causality tests in conjunction with Akaike's final prediction error criterion. The results indicate that measures approximating monetary policy and market returns play an important role in causing changes in real estate returns. In particular, our findings suggest that base money and market returns have had significant lagged effects on current real estate returns.