Evaluation of dynamic stochastic general equilibrium models based on distributional comparison of simulated and historical data

We take as a starting point the existence of a joint distribution implied by different dynamic stochastic general equilibrium (DSGE) models, all of which are potentially misspecified. Our objective is to compare “true” joint distributions with ones generated by given DSGEs. This is accomplished via comparison of the empirical joint distributions (or confidence intervals) of historical and simulated time series. The tool draws on recent advances in the theory of the bootstrap, Kolmogorov type testing, and other work on the evaluation of DSGEs, aimed at comparing the second order properties of historical and simulated time series. We begin by fixing a given model as the “benchmark” model, against which all “alternative” models are to be compared. We then test whether at least one of the alternative models provides a more “accurate” approximation to the true cumulative distribution than does the benchmark model, where accuracy is measured in terms of distributional square error. Bootstrap critical values are discussed, and an illustrative example is given, in which it is shown that alternative versions of a standard DSGE model in which calibrated parameters are allowed to vary slightly perform equally well. On the other hand, there are stark differences between models when the shocks driving the models are assigned non-plausible variances and/or distributional assumptions.     

A versatile and robust metric entropy test of time-reversibility,and other hypotheses

We examine the performance of a metric entropy statistic as a robust test for time-reversibility (TR), symmetry, and serial dependence. It also serves as a measure of goodness-of-fit. The statistic provides a consistent and unified basis in model search, and is a powerful diagnostic measure with surprising ability to pinpoint areas of model failure. We provide empirical evidence comparing the performance of the proposed procedure with some of the modern competitors in nonlinear time-series analysis, such as robust implementations of the BDS and characteristic function-based tests of TR, along with correlation-based competitors such as the Ljung–Box Q-statistic. Unlike our procedure, each of its competitors is motivated for a different, specific, context and hypothesis. Our evidence is based on Monte Carlo simulations along with an application to several stock indices for the US equity market.     

Finite sample multivariate structural change tests with application to energy demand models

This paper considers finite sample motivated structural change tests in the multivariate linear regression model with application to energy demand models, in which case commonly used structural change tests remain asymptotic. As in Dufour and Kiviet [1996. Exact tests for structural change in first-order dynamic models. Journal of Econometrics 70, 39–68], we account for intervening nuisance parameters through a two-stage maximized Monte Carlo test procedure. Our contributions can be classified into five categories: (i) we extend tests for which a finite-sample theory has been supplied for Gaussian distributions to the non-Gaussian context; (ii) we show that Bai et al. [1998. Testing and dating common breaks in multi-variate time series. The Review of Economic Studies 65 (3), 395–432] test severely over-rejects and propose exact variants of this test; (iii) we consider predictive break test approaches which generalize tests in Dufour [1980. Dummy variables and predictive tests for structural change. Economics Letters 6, 241–247] and Dufour and Kiviet [1996. Exact tests for structural change in first-order dynamic models. Journal of Econometrics 70, 39–68]; (iv) we propose exact (non-Bonferonni based) extensions of the multivariate outliers test from Wilks [1963. Multivariate statistical outliers. Sankhya Series A 25, 407–426] to models with covariates; (v) we apply these tests to the energy demand system analyzed by Arsenault et al. [1995. A total energy demand model of Québec: forecasting properties. Energy Economics 17 (2), 163–171]. For two out of the six industrial sectors analyzed over the 1962–2000 period, break and further goodness-of-fit and diagnostic tests allow to identify (and correct) specification problems arising from historical regulatory changes or (possibly random) industry-specific effects. The procedures we propose have potential useful applications in statistics, econometrics and finance (e.g. event studies).     

基于价值网的移动通信运营商标准竞争战略研究

标准是经过各方协商并由公认部门公布的统一规范。随着中国进入后WTO时代,特别是移动通信3G时代的来临,基于标准的竞争日益成为通信技术领域企业竞争的战略方向。而价值网是价值链向外延伸发展的高级阶段,在标准竞争战略中占有重要地位。文章从技术进步与融合背景下运营商所面临的机遇与挑战入手,构建了一个标准竞争战略的分析框架,探讨了移动通信运营商基于价值网的标准竞争战略。     

Short sellers and insider trading profitability: A natural experiment

We examine the impact of short sellers on insider trading profitability using a natural experiment of a pilot program which relaxed short-selling constraints for randomly selected pilot stocks. We find that pilot firms experienced a significant decrease in insider trading profitability during the pilot program. The results are more pronounced for the pilot firms with poor information quality, and for the pilot firms without corporate restrictions on insider trading. Our evidence suggests that short sellers serve an important market disciplinary role by reducing insider trading profitability.     

Terrorism activities and long-term annual management forecasts

We study the effects of terrorist attacks on firms’ long-term annual management earnings forecasts bias. We find that the managers of firms located closer to the epicenters of attacks are more likely to issue optimistic long-term annual earnings forecasts relative to the managers of a control group of unaffected firms. The exposure effect is stronger for more severe terrorist events, and firms with more uncertain fundamentals and less geographic diversification. In addition, we document that managers’ forecast optimism intensifies for firms with stronger negative stock market reaction to the terrorist event, for CEOs with higher ability and for companies that are more likely to issue equity or engage in acquisitions following the terrorist event. Overall, our results are consistent with the idea that long-term annual earnings forecasts are used by managers to counterbalance the short-term pessimistic response to terrorist attacks.     

Media attention and regulatory efficiency of corporate violations: Evidence from China

We examine the influence of media attention on the regulatory efficiency of corporate violations in a restrictive media environment. Using a hand-collected sample of corporate violations in China during 1998–2018, we find that fraudulent firms accompanied by more negative media attention are associated with a higher hazard rate of the violation being investigated and enforced. The effect is not diminished by the political connections of the fraudulent firms and is robust after controlling for potential confounding factors. Our findings suggest that by influencing regulatory efficiency, the media serve as an effective governance mechanism even in markets with strict media control.     

我国出口集装箱运价指数研究

文章运用X-12-ARIMA方法对中国集装箱运价指数序列进行了季节调整，并采用TRAMO／SEATS季节调整方法处理了节假日因素的调整问题，然后对两个模型进行了比较，利用优选出来的模型将原序列分解成了各影响因素，最后对中国出口集装箱运价指数进行了精确的短期预测。     

适应需求的技术才能最终驱动市场--浅论技术与市场的关系

本文从移动短信业务的蓬勃发展和铱星的"陨落"这正反两方面入手,有针对性地分析了技术与市场的关系,指出了只有适应需求的技术才能最终驱动市场.同时,就如何以市场观念正确认识和把握第三代移动通信(3G)的发展提出了建设性意见.