哈尔滨市人口发展历程及趋势

根据人口普查等文献资料,对哈尔滨市人口发展历程与现状进行深入分析,并对其未来发展趋势进行预测。预测结果表明:哈尔滨市人口规模将保持增长趋势,人口老龄化程度也将不断加深。据此,对哈尔滨市人口发展面临的问题提出了相应对策。     

加工贸易对我国贸易增长的贡献

我国加工贸易形式从大的方面讲分为来料加工和进料加工两种形式。改革开放27年来,我国加工贸易得到了飞速发展。并且,我国成为在国际贸易体系中具有影响力的贸易大国,主要得益于加工贸易的发展。     

A comparison of alternative rate estimators in some frequently used growth models

This paper deals with the linear, exponential and Gompertz models and compares the bias and variance of a number of estimators of the growth-rate parameters of these models. Some of these estimators have been commonly recommended in the literature and others are most frequently used in empirical practice. The present analysis points to the strengths and weaknesses of the estimators in their usage.     

A Numerical Method for Estimating the Variance of Age at Maximum Growth Rate in Growth Models

Studies on maturation and body composition mention age at peak height velocity (PHV) as an important measure that could predict adulthood outcome. The age at PHV is often derived from growth models such as the triple logistic fitted to the stature (height) data. Theoretically, for a well-behaved growth function, age at PHV could be obtained by setting the second derivative of the growth function to zero and solving for age. Such a solution obviously depends on the parameters of the growth function. Therefore, the uncertainty in the estimation of age at PHV resulting from the uncertainty in the estimation of the growth model, need to be accounted for in the models in which it is used as a predictor. Explicit expressions for the age at PHV and, consequently the variance of the estimate of the age at PHV, do not exist for some of the commonly used nonlinear growth functions, such as the triple logistic function. Once an estimate of this variance is obtained, it could be incorporated in subsequent modeling either through measurement error models or by using the inverse variances as weights. A numerical method for estimating the variance is implemented. The accuracy of this method is demonstrated through comparisons in models where explicit solution for the variance exists. The method of estimating the variance is illustrated by applying to growth data from the Fels study and subsequently used as weights in modeling two adulthood outcomes from the same study.     

Multivariate analysis with a stationary time series covariance structure

When a covariance matrix has a pattern associated with a stationary time series on the errors, it is shown how certain hypothesis testing problems In multivariate analysis can be transformed into a product of two similar multivariate problems that each involve unpatterned covariance matrices.     

Unit Roots,Level Shifts,and Trend Breaks in Per Capita Output: A Robust Evaluation

Determining whether per capita output can be characterized by a stochastic trend is complicated by the fact that infrequent breaks in trend can bias standard unit root tests towards nonrejection of the unit root hypothesis. The bulk of the existing literature has focused on the application of unit root tests allowing for structural breaks in the trend function under the trend stationary alternative but not under the unit root null. These tests, however, provide little information regarding the existence and number of trend breaks. Moreover, these tests suffer from serious power and size distortions due to the asymmetric treatment of breaks under the null and alternative hypotheses. This article estimates the number of breaks in trend employing procedures that are robust to the unit root/stationarity properties of the data. Our analysis of the per capita gross domestic product (GDP) for Organization for Economic Cooperation and Development (OECD) countries thereby permits a robust classification of countries according to the “growth shift,” “level shift,” and “linear trend” hypotheses. In contrast to the extant literature, unit root tests conditional on the presence or absence of breaks do not provide evidence against the unit root hypothesis.     

经济增速放缓与经济波动对居民福利影响的阶段差异分析

 本文基于中国1952-2007年时序数据定量研究经济增速放缓的福利损失和经济波动的福利损失,并侧重考察两种福利损失的大小关系在改革开放和经济体制改革目标确立前后的阶段差异。研究发现,无论是总体而言,还是在中国经济发展的不同阶段,经济波动的福利损失并不必然远小于经济增速放缓的福利损失,在相关参数的合理取值范围内,经济波动的福利损失大于经济增速放缓的福利损失是相当普遍的情形。因此,中国政府部门在重视长期经济增长的同时,不能草率否定短期经济稳定的重要性。     

农村居民消费增长比平稳更重要

 本文将消费习惯引入Lucas (1987)模型,采用农村五等份收入户的人均消费数据进行数值模拟,结果发现: 消费增长比消费平稳更重要,且收入等级越高,这种相对重要性就越突出。相对风险规避系数一定时,两类福利成本之比随习惯强度变化的轨迹呈倒U型; 习惯强度一定时,两类福利成本之比随相对风险规避系数的增大而递减。相对于其他等级的收入户,促进消费增长的经济政策为高收入户带来相对较多的福利,而平抑消费波动的经济政策能为低收入户带来较多的福利。因此,政府在促进农村居民消费增长的同时,也应重视消费波动给低收入群体造成的福利成本。     

Covid-19 in Central America: Firm resilience and policy responses on employment

This paper examines how government support interacts with firm-level resilience capabilities in the reduction of layoffs among formal firms in Central America. Our analysis suggests that government support measures play a role in reducing the probability of layoffs among firms with only dynamic resilience capabilities (i.e., those that are developed after the pandemic onset). The effect of government support is not statistically different from the effect of static resilience capabilities alone (i.e., those that were present before the pandemic); thus, in firms with such capabilities, the effect of government support will be marginal. These results hold across sectors - exhibiting a marginally higher treatment effect in service sectors. Our results do not imply that Covid-19 supportive measures are to be disregarded, but instead raise the question of how government support policies could improve the allocation of support among firms in times of crises. Moreover, it underlines the necessity of policies that enhance resilience more broadly – a task that hints at structural issues and requires continuous government support in lieu of ad-hoc measures.