Type-I-error rate inflation in mixed models for repeated measures caused by ambiguous or incomplete model specifications

Pre-specification of the primary analysis model is a pre-requisite to control the family-wise type-I-error rate (T1E) at the intended level in confirmatory clinical trials. However, mixed models for repeated measures (MMRM) have been shown to be poorly specified in study protocols. The magnitude of a resulting T1E rate inflation is still unknown. This investigation aims to quantify the magnitude of the T1E rate inflation depending on the type and number of unspecified model items as well as different trial characteristics. We simulated a randomized, double-blind, parallel group, phase III clinical trial under the assumption that there is no treatment effect at any time point. The simulated data was analysed using different clusters, each including several MMRMs that are compatible with the imprecise pre-specification of the MMRM. T1E rates for each cluster were estimated. A significant T1E rate inflation could be shown for ambiguous model specifications with a maximum T1E rate of 7.6% [7.1%; 8.1%]. The results show that the magnitude of the T1E rate inflation depends on the type and number of unspecified model items as well as the sample size and allocation ratio. The imprecise specification of nuisance parameters may not lead to a significant T1E rate inflation. However, the results of this simulation study rather underestimate the true T1E rate inflation. In conclusion, imprecise MMRM specifications may lead to a substantial inflation of the T1E rate and can damage the ability to generate confirmatory evidence in pivotal clinical trials.     

通货膨胀率和股票收益率的相关性的实证研究——基于马尔可夫转换模型

通过建立马尔可夫向量误差修正模型，分别在高通胀和低通胀两个区制内研究股票实际收益率和通货膨胀率的相关性。根据实证分析结果，股指和CPI之间存在正向协整关系，协整误差对CPI 的短期波动具有正向的修正作用。对于同步相关性，在低通胀区制内，股票收益率和通货膨胀率正相关，在高通胀区制内，股票收益率和通货膨胀率负相关。短期相关性不显著。     

监管政策影响了债券评级质量吗？——理论框架与经验证据

近年来,减少金融监管对信用市场的干扰已成为我国监管部门关注的重点问题。通过构建包含监管部门、评级机构和债券发行方等主体在内的三阶段博弈论模型,从理论上探讨了监管政策对债券评级质量的影响。研究发现,监管部门提高债券评级要求会导致市场充斥大量违约风险较高的债券。为了增加评级收入,评级机构会给出虚高评级。在此基础上,基于2017年4月7日中国证券登记结算有限责任公司调整交易所债券市场上信用债券质押入库资格这一准自然实验,利用2015—2019年我国企业债发行数据,采用PSM-DID方法进一步实证检验了监管政策调整对债券评级质量的影响。经验证据表明,提高债券资格门槛会助推债券评级上升,但政策实施前后债券的利差并未发生显著变化,即监管政策调整助推了债券评级虚高。因此,监管部门需改变通过评级结果来识别债券风险的传统监管思路,应尝试构建多元化的信用监管机制。     

国际农产品价格对中国通货膨胀的传递效应

针对国际农产品金融化背景下,国际农产品价格对中国通货膨胀的传递效应动态变化研究的不足,引入了状态空间模型和BEKK-GARCH模型,基于2000年1月至2015年1月的月度数据,对传递系数的动态变化特征及金融变量对传递系数的影响展开了实证分析。结果显示：国际农产品金融化背景下,尤其在2008年金融危机以后,国际农产品价格向中国通货膨胀的传递系数为正,且呈现出明显的上升趋势;国际农产品期货价格、国际石油价格、人民币汇率和国际流动性水平均对传递系数有正向促进作用;国际农产品期货价格、国际石油价格和国际流动性水平相互影响,对传递系数存在ARCH型波动溢出效应。     

我国经济适度稳定增长的货币供给边界研究(一)──货币供给边界的理论分析

提出货币供给边界的概念,从货币数量论、潜在资源论及通过对奥肯定律和菲利普斯曲线的推导,揭示货币供给、通货膨胀和经济增长三者之间密不可分的关系,并证明在实践中客观存在的货币供给边界。