Three Corrected Score Tests for Generalized Linear Models with Dispersion Covariates

We develop three corrected score tests for generalized linear models with dispersion covariates, thus generalizing the results of Cordeiro , Ferrari and Paula (1993) and Cribari-Neto and Ferrari (1995) . We present, in matrix notation, general formulae for the coefficients which define the corrected statistics. The formulae only require simple operations on matrices and can be used to obtain analytically closed-form corrections for score test statistics in a variety of special generalized linear models with dispersion covariates. They also have advantages for numerical purposes since our formulae are readily computable using a language supporting numerical linear algebra. Two examples, namely, iid sampling without covariates on the mean or dispersion parameter oand one-way classification models, are given. We also present some simulations where the three corrected tests perform better than the usual score test, the likelihood ratio test and its Bartlett corrected version. Finally, we present a numerical example for a data set discussed by Simonoff and Tsai (1994) .     

The British low-wage sector and the employment prospects of the unemployed

Are low wages a way for the unemployed to switch to higher-paying jobs? Using data from the British Household Panel Survey, the labour market dynamics of unemployed, low-paid and higher-paid employed men are analysed. Moreover, the respective (un)employment duration and occupational skill level are accounted for. Results show that in general low wages significantly reduce the risk of future unemployment and increase the chances of ascending the salary ladder, especially in the case of long-term unemployment (>360 days). Furthermore, the occupational skill level has a substantial influence on the upward mobility of low-paid jobs: individuals working in the initial period in a low-paid and higher-skilled occupation have on average an 11 percentage points higher probability of entering higher pay compared to when working in a low-paid and low-skilled occupation.     

ML– and semiparametric estimation in logistic models with incomplete covariate data

ML–estimation of regression parameters with incomplete covariate information usually requires a distributional assumption regarding the concerned covariates that implies a source of misspecification. Semiparametric procedures avoid such assumptions at the expense of efficiency. In this paper a simulation study with small sample size is carried out to get an idea of the performance of the ML–estimator under misspecification and to compare it with the semiparametric procedures when the former is based on a correct assumption. The results show that there is only a little gain by correct parametric assumptions, which does not justify the possibly large bias when the assumptions are not met. Additionally, a simple modification of the complete case estimator appears to be nearly semiparametric efficient.     

The price relationship between organic and non-organic vegetables in the U.S.: evidence from Nielsen scanner data

This study investigates price relationships between organic and conventional carrots, tomatoes, and lettuce in the U.S. utilizing Nielsen scanner data from 2006–2015. We employ a threshold vector error correction model (TVECM), threshold vector autoregressive model (TVAR), and threshold cointegration test to test whether market integration exists between organic and conventional vegetables as well as the existence of asymmetric price transmission. The results find positive long-run relationships between organic and conventional prices of carrots and tomatoes and show the existence of asymmetric price transmission in price pairs of lettuce and tomatoes. Our findings suggest that the price relationship between organic and conventional vegetables varies by characteristics, such as shelf life, volatility in the price premium, and substitutability.     

资本形成、工业化与经济增长:中国的转轨特征

把中国的经济转轨、增长与工业化联系起来是本文的一个尝试。作者认为 ,中国的经济增长在近年来越来越表现出静态的特征 ,至今尚不具备持续的动态改进的力量 ,而中国在 2 0世纪 80年代以后的转轨过程则又典型地表现为以新兴工业部门的进入和扩张为特征的持续的工业化过程。本文给出了一个帮助理解转轨后中国经济增长可持续性的概念框架和经验描述。在这个框架里 ,中国的经济增长在过去 1 0年来所表现出的下降趋势可以由过度的工业化进程来解释。     

揭示"制度与增长关系之谜"的一个研究视角——基于中国经济转型与经济增长关系的实证研究(1978-2004)

本文通过对中国经济转型与经济增长之间的实证研究,发现经济增长是直接推动经济体制转型深化的内在动力,而经济转型虽然对经济增长有长期的影响作用,但这种作用却不是决定性的.在制度与增长二者关系中,制度虽然是影响增长的长期重要因素,但这种影响却不是决定性的;而恰恰相反,增长对制度的影响却是决定性的.这说明制度创新在增长的大背景中更易达到,而中国改革成功的经验也充分证明了这一点.     

北京先行经济指数研究

"北京先行经济指数"是我国第一个区域性先行经济指数,在试运行中取得了很好的效果。该指数以我国现行统计制度为基础,紧密结合北京实际,通过构造基准循环、"提取"先行指标、编制指数、返回检验等步骤,对北京先行经济指数的科学性和有效性进行了分析。先行指数超前GDP增速变化4～8个月这一重要研究结论在返回检验中得到了很好的证实。     

陕西构建和谐社会须切实控制出生人口性别比

出生人口性别比保持在正常值域是和谐社会的一个重要基础。陕西出生人口性别比显著高于正常值，且有加剧趋势。将对构建和谐社会带来严重后果，必须采取多种措施进行控制和治理。     

铸铁的脆性分析

本文通过灰口铸铁的拉抻实验、压缩实验、扭转实验,用材料力学的分析方法,对灰口铸铁的极限应力,即拉伸极限应力σ_L,压缩极限应力σ_y 以及剪切极限应力τ的比较,得出脆性材料灰口铸铁的脆性特征为σ_L<τ<σ_y。     

Cross-hedging foreign currency risk: Empirical evidence from an error correction model

In this article, the traditional price change hedge ratio estimation method is extended by applying the theory of cointegration in the case of cross-hedging of spot exchange risk of the Belgian franc (BF), the Italian lira (IL), and the Dutch guilder (NG) with U.S. Dollar Index futures contracts. Previous studies ignore the last period's equilibrium error and short-run deviations. The findings of this study indicate that the hedge ratio estimated by the error correction method is superior to that obtained from the traditional method, as evidenced by the likelihood ratio test and out-of-sample forecasts. Hedgers will be able to control the risk of their portfolios more effectively at a lower cost.