基于Probit回归的小企业债信评级模型及实证

小企业债信评级系指评价一笔小企业的债务信用资质的高低和债务违约损失率的大小.它事关银行贷款的风险管理以及合格的小企业能否得到融资.因此、债信评级的指标必须能直接鉴别小企业的违约状态.以等级评分和排序为目的的现有的信用评级体系并不评价一笔债务违约损失率大小,现有的信用评级体系也没有任何证据表明其评级指标体系与企业违约状态的鉴别能力有关.本研究根据指标对违约状态鉴别能力的大小遴选指标体系,建立了小企业债信评级体系.本文的创新与特色一是在偏相关系数大于0.7、反映信息重复的一对高度相关的指标中,删除F值小、对小企业违约状态判别能力弱的指标,既避免了第一次筛选后评级指标体系的信息冗余、又避免了误删对违约状态影响大的指标.改变了现有研究评级体系指标的遴选与指标违约状态的鉴别能力无关的状况.二是通过求解违约状态变量与评价指标之间Probit回归方程的回归系数β和回归系数的标准误差sEβ,构建Wald统计量对回归系数β的显著水平进行检验,剔除对小企业违约状态影响小的、回归系数β不显著的指标,保证了第二次筛选出的指标能显著区分企业的违约状态.三是研究表明本文构造的指标体系的感受型曲线ROC的面积AUC大于0.9,不仅保证单个指标能有效区分违约状态,同时确保了整体构建的指标体系对违约状态具有极强的鉴别能力.四是研究结果表明,满足信用等级越高、违约损失率越低的小企业债信评级指标体系的非财务指标权重为56％.五是通过对1 231笔小企业贷款数据进行实证,结果表明:速动比率、总资产增长率、行业景气指数等23个指标能够显著区分小企业的违约状态.     

Flexible uncertainty in mixture models for ordinal responses

In classical mixture models for ordinal data with an uncertainty component, the Uniform distribution is used to model indecision. In the approach proposed here, the discrete Uniform distribution is replaced by a more flexible distribution, which is centered in the middle of the response categories. The resulting model allows to distinguish between a tendency to middle categories and a tendency to extreme categories. By linking these preferences to explanatory variables, one can investigate which persons show a tendency to these response styles. It is demonstrated that severe bias might occur if inadvertently the Uniform distribution is used to model uncertainty. An application to attitudes on the performance of health services illustrates the advantages of the more flexible model.     

Bayesian estimation of a proportional hazards model for double-censored durations

Double-censored data consist of uncensored, left- and right-censored observations and occur in survival time analysis. In this paper, parametric Bayes estimation is investigated for a proportional hazards model with durations subject to double-censoring. We prove consistency and asymptotic normality of the posterior mean with the Bernstein–von Mises theorem. In addition, we estimate asymptotic standard errors. A simulation study shows that the finite-sample performance is similar to that of the maximum likelihood estimator. Finally, the proposed model is applied to rating transition data. The analysis suggests that an upgrade of a rating increases the duration in that class by about 10 days on average.     

基于MCMC模拟和伪似然估计法的交叉分类信度模型费率厘定简

针对传统交叉分类信度模型计算复杂且在结构参数先验信息不足的情况下不能得到参数无偏后验估计的问题，利用MCMC模拟和GLMM方法，对交叉分类信度模型进行实证分析证明模型的有效性。结果表明：基于MCMC方法能够动态模拟参数的后验分布，并可提高模型估计的精度；基于GLMM能大大简化计算过程且操作方便，可利用图形和其它诊断工具选择模型，并对模型实用性做出评价。     

On Seidenfeld‘s Criticism of Sophisticated Violations of the Independence Axiom 1

An agent who violates independence can avoid dynamic inconsistency in sequential choice if he is sophisticated enough to make use of backward induction in planning. However, Seidenfeld has demonstrated that such a sophisticated agent with dependent preferences is bound to violate the principle of dynamic substitution, according to which admissibility of a plan is preserved under substitution of indifferent options at various choice nodes in the decision tree. Since Seidenfeld considers dynamic substitution to be a coherence condition on dynamic choice, he concludes that sophistication cannot save a violator of independence from incoherence. In response to McClennens objection that relying on dynamic substitution when independence is at stake must be question-begging, Seidenfeld undertakes to prove that dynamic substitution follows from the principle of backward induction alone, provided we assume that the agents admissible choices from different sets of feasible plans are all based on a fixed underlying preference ordering of plans. This paper shows that Seidenfelds proof fails: depending on the interpretation, it is either invalid or based on an unacceptable assumption.     

我国商业银行信用评级制度的发展与完善

文章首先分析了国际商业银行信用评级制度的特点,继而指出了我国当前商业银行信用评级制度存在的缺陷和不足,最后提出了如何构建和完善我国商业银行信用评级制度的具体策略和措施。     

我国个人所得税改革措施的探讨

随着我国加入WTO和国民经济的持续增长,个人所得税的不合理性越来越明显,已经影响了我国经济的发展,从免征额、税率和级距、税收征管三个方面借鉴国际通行做法,根据我国实际情况探讨了个人所得税改革的方向和举措。     

Some Limitations of Qualitative Risk Rating Systems

Qualitative systems for rating animal antimicrobial risks using ordered categorical labels such as “high,”“medium,” and “low” can potentially simplify risk assessment input requirements used to inform risk management decisions. But do they improve decisions? This article compares the results of qualitative and quantitative risk assessment systems and establishes some theoretical limitations on the extent to which they are compatible. In general, qualitative risk rating systems satisfying conditions found in real‐world rating systems and guidance documents and proposed as reasonable make two types of errors: (1) Reversed rankings, i.e., assigning higher qualitative risk ratings to situations that have lower quantitative risks; and (2) Uninformative ratings, e.g., frequently assigning the most severe qualitative risk label (such as “high”) to situations with arbitrarily small quantitative risks and assigning the same ratings to risks that differ by many orders of magnitude. Therefore, despite their appealing consensus‐building properties, flexibility, and appearance of thoughtful process in input requirements, qualitative rating systems as currently proposed often do not provide sufficient information to discriminate accurately between quantitatively small and quantitatively large risks. The value of information (VOI) that they provide for improving risk management decisions can be zero if most risks are small but a few are large, since qualitative ratings may then be unable to confidently distinguish the large risks from the small. These limitations suggest that it is important to continue to develop and apply practical quantitative risk assessment methods, since qualitative ones are often unreliable.     

理想与挑战:"绿色收视率"如何实现

"绿色收视率"概念的提出及其受到广泛关注,反映了社会对当前电视媒介片面追求收视率引发的节目"文化空壳"现象的忧虑。"绿色收视率"理想的实现至少面临三方面的挑战:收视评估体系的各项指标数值难以准确科学把握;高素质的电视经理人才匮乏;电视媒体的成长环境与市场机制存在"硬性"冲突。有针对性地寻找突破是解决这些问题的关键。     

5G时代跨屏收视测量标准的融合进路

5G时代将加速实现受众跨屏视频观看习惯的养成,旧收视率测量体系不能满足当前大视频行业的发展需要,急需建立新的“通行货币”。成本和技术手段可以达成跨屏测量的数据融合,但行业竞争所导致的数据壁垒是测量标准迟迟无法制定的根本原因。本研究基于未来5G应用的政策基础性构架或许可为跨屏收视测量提供解决的制度路径。