Choice of the ridge factor from the correlation matrix determinant

Ridge regression is the alternative method to ordinary least squares, which is mostly applied when a multiple linear regression model presents a worrying degree of collinearity. A relevant topic in ridge regression is the selection of the ridge parameter, and different proposals have been presented in the scientific literature. Since the ridge estimator is biased, its estimation is normally based on the calculation of the mean square error (MSE) without considering (to the best of our knowledge) whether the proposed value for the ridge parameter really mitigates the collinearity. With this goal and different simulations, this paper proposes to estimate the ridge parameter from the determinant of the matrix of correlation of the data, which verifies that the variance inflation factor (VIF) is lower than the traditionally established threshold. The possible relation between the VIF and the determinant of the matrix of correlation is also analysed. Finally, the contribution is illustrated with three real examples.     

The zero-inflated Poisson model and the decayed, missing and filled teeth index in dental epidemiology

For frequency counts, the situation of extra zeros often arises in biomedical applications. This is demonstrated with count data from a dental epidemiological study in Belo Horizonte (the Belo Horizonte caries prevention study) which evaluated various programmes for reducing caries. Extra zeros, however, violate the variance–mean relationship of the Poisson error structure. This extra-Poisson variation can easily be explained by a special mixture model, the zero-inflated Poisson (ZIP) model. On the basis of the ZIP model, a graphical device is presented which not only summarizes the mixing distribution but also provides visual information about the overall mean. This device can be exploited to evaluate and compare various groups. Ways are discussed to include covariates and to develop an extension of the conventional Poisson regression. Finally, a method to evaluate intervention effects on the basis of the ZIP regression model is described and applied to the data of the Belo Horizonte caries prevention study.     

Long‐Term Debt and Optimal Policy in the Fiscal Theory of the Price Level

The fiscal theory says that the price level is determined by the ratio of nominal debt to the present value of real primary surpluses. I analyze long‐term debt and optimal policy in the fiscal theory. I find that the maturity structure of the debt matters. For example, it determines whether news of future deficits implies current inflation or future inflation. When long‐term debt is present, the government can trade current inflation for future inflation by debt operations; this tradeoff is not present if the government rolls over short‐term debt. The maturity structure of outstanding debt acts as a “budget constraint” determining which periods' price levels the government can affect by debt variation alone. In addition, debt policy—the expected pattern of future state‐contingent debt sales, repurchases and redemptions—matters crucially for the effects of a debt operation. I solve for optimal debt policies to minimize the variance of inflation. I find cases in which long‐term debt helps to stabilize inflation. I also find that the optimal policy produces time series that are similar to U.S. surplus and debt time series. To understand the data, I must assume that debt policy offsets the inflationary impact of cyclical surplus shocks, rather than causing price level disturbances by policy‐induced shocks. Shifting the objective from price level variance to inflation variance, the optimal policy produces much less volatile inflation at the cost of a unit root in the price level; this is consistent with the stabilization of U.S. inflation after the gold standard was abandoned.     

我国通货膨胀名义成因和实际成因的检验分析

货币供给扩张是导致通货膨胀的名义因素,总需求和总供给扩张是导致通货膨胀的实 际因素。通过统计检验,我们发现,货币供给增长率和通货膨胀率之间不存在显著的协整关系,但 消费需求增长率对通货膨胀率具有显著的Granger影响,这说明我国价格水平变化具有名义需求和 实际需求的双重驱动迹象。因此抑制通货膨胀时,控制名义因素效果比较明显,而治理通货紧缩 时,实际因素扩张的作用则更为显著。     

通胀周期、金融抑制与企业存货的动态调整

企业存货调整策略的准确识别是有效管理通胀预期的必要条件。本文基于非线性交互效应面板误差纠正模型、从微观层面研究在通胀周期不同阶段,企业存货调整的具体特征。实证结果与反事实对比仿真实验均表明:主导企业存货策略性调整的是通胀预期而不是实际通胀水平。与社会的经验判定不同,企业存货调整对通胀表现出逆周期特征。对大部分行业而言,低通胀阶段,通胀预期的收益效应强于存货调整的成本效应,货币调控无效;高通胀阶段,通胀预期弱化,成本效应凸显,货币调控才有效。两种机制的阈值通胀率约为3.4%,所以,将通胀调控上限定为3.5%符合企业市场行为的特征。各行业存货策略对货币调控、通胀预期的灵敏度有显著差异,房地产、批发零售、机械设备较为敏感,最不敏感的是食品行业。     

土地供给对通货膨胀的动态影响分析

通货膨胀是宏观经济学研究的一个热点问题,而土地供给对通货膨胀的影响又是当前非常现实的问题,特别对于中国这样的发展中国家,该问题的现实意义更为突出。利用AD-AS模型和面板VAR模型,研究土地供给对通货膨胀的动态影响,结果表明:从脉冲响应函数看,在受到土地供给冲击时,通货膨胀在同期没有发生变化,在第一年受到正的影响,但在第二年之后主要受到负的影响,并且累积响应为负;从方差分解看,土地供给对通货膨胀波动的解释程度较小。政府可以通过对土地供给的调控,使中国宏观经济处于"高增长,低膨胀"的平稳状态。     

中国货币政策利率工具调控的数量效应与价格效应分析

通过构建VAR模型,实证分析中国货币政策利率工具调控的数量效应和价格效应。结论显示:在市场流动性过剩的金融环境下,商业银行信贷规模对利率政策的敏感性增强,货币政策利率工具调控的数量效应有所扩大;由于短期"费雪效应"的存在,弱化了货币政策利率工具调控的价格效应;货币政策的数量型工具对抑制通货膨胀见效相对更快。因此,货币当局在金融调控中,需要根据经济发展的不同周期阶段和金融环境,合理搭配运用价格型和数量型货币政策工具,提高货币政策的调控效率和预期效应。     

2012年中国物价走势分析与判断

2011年,我国经济增长由政策刺激向自主增长有序转变,物价总水平高位运行,上涨势头初步得到控制,同时经济增长呈平稳减速态势。初步判断,本轮物价涨幅已经见顶,价格运行拐点特征已得到确认,2011年GDP增长9.2%,CPI上涨5.4%。从2012年发改委设定的4%的CPI价格调控目标来看,2012年价格翘尾因素将显著降低,物价总水平将呈现温和上涨态势,国内资源要素价格改革压力加大。虽然控制物价上涨已经逐渐淡出第一调控目标,但是在导致本轮价格上涨的因素一个都没有消除前,就此判断未来价格风险已消除还为时过早。     

我国利率政策的有效性研究

在传统IS-LM/AS模型基础上放松三条假设后建立了一个简化的总供需模型,籍此探讨利率政策的价格效应及利率政策的有效性。研究表明,在未完全实现利率市场化的条件下,中国的利率政策存在价格效应,且利率政策在控制货币供应量方面效能较低,易导致短期内价格效应大于需求效应,限制了利率政策的选择空间;总体来看,中国在控制物价过程中倚重于数量型货币政策工具是现阶段的最优选择,可有效化解利率政策的价格效应,促进货币政策有效传导。     

欧债危机背景下我国通货膨胀治理研究

改革开放30年以来,我国经济取得了举世瞩目的成绩,但也出现了四次大的通货膨胀,目前欧债危机越演越烈,对世界经济包括我国经济必将带来巨大的影响,极有可能助推我国已经出现的通货膨胀。文章通过对我国历次通货膨胀原因的探悉和成功治理对策的研究,认为要充分发挥市场调控功能,加快经济增长方式的转变,合理运用国家宏观调控政策治理我国可能出现的复合式通货膨胀。