英语翻译In particular,this occurs when the lagged levels of the series are weakly correlated with subsequent first-differences as normally happens when the series is highly persistent.The first-differenced GMM estimator has been found to have poo

英语翻译In particular,this occurs when the lagged levels of the series are weakly correlated with subsequent first-differences as normally happens when the series is highly persistent.The first-differenced GMM estimator has been found to have poo
英语翻译
In particular,this occurs when the lagged levels of the series are weakly correlated with subsequent first-differences as normally happens when the series is highly persistent.
The first-differenced GMM estimator has been found to have poor fi nite
sample properties in terms of bias and imprecision.In particular,this occurs
when the lagged levels of the series are weakly correlated with subsequent fi rstdifferences as normally happens when the series is highly persistent.Hence the
instruments available for the fi rst-differenced equations are weak (Blundell and
Bond,1998).Blundell and Bond have shown that the fi rst-differenced GMM
estimator could be subject to a large downward bias.This is particularly severe
when the time period being considered for each unit is small.For example,in most
cross-country growth regressions,the time period is reduced to a small number of
τ-period averages as in our case.这是这句话的上下文，输入不了太多了。

英语翻译In particular,this occurs when the lagged levels of the series are weakly correlated with subsequent first-differences as normally happens when the series is highly persistent.The first-differenced GMM estimator has been found to have poo
特别的,若级数各级滞后水平和一阶差分呈弱相关,这（种情况）就会发生,正如级数高度重复（或：尤其反复出现、特别持久,缺上下文,请LZ补充）时一般都会有（一样）.
供参.
现已发现,在偏倚、不精确性两方面,一阶差分广义矩（法）估计值的样本特性极其有限.特别是当级数各级滞后水平和一阶差分呈弱相关时,这（种情况）就会发生,正如级数极为（或：高度）重复（或：反复出现）时一般都会有（一样）.基于此,用于一阶差分方程式/等式的方法作用不大（Blundell和Bond,1998年）.Blundell和Bond已证明,一阶差分广义矩很大程度上受向下偏倚影响.若因各个单元/部分都不大而考虑时间周期（的话）,上述情况就尤为严重了.譬如,以我们个案为例,大多数跨国增长回归（模型）中,时间周期都降至1周期平均值这种小量水平.
供参.