【摘要】 利用2001—2004年中国海关月度贸易数据,本文对中美进出口贸易统计的"偏年度误差"进行测度分析。研究结果表明:中国对美贸易企业的进出口动态在跨月间存在较为明显的差异,从事进出口活动的新企业数量的各月平均占比随着时间的推移总体呈下降态势;采用日历年统计方式计算中国企业的年均进出口增长率以及按月统计的年均进出口增长率,前者会出现大幅高估的现象,且以首个贸易时间段最为明显,而后者则会产生低估前8、9个月的进出口增长率以及高估后3、4个月的进出口增长率的统计误差;采用日历年统计方式来计算中国企业的相对进出口水平,会引发相对进出口额的低估以及相对进出口增长率的高估问题;剔除"偏年度效应"后,扩展边际在进出口增长分解中的贡献率显著上升,这说明传统的日历年统计方式低估了扩展边际的作用。综上,忽视"偏年度效应"容易引致贸易统计指标出现失真失实等统计幻象,针对此引入相应的修正方法并评估其政策效应,应成为未来完善外贸统计标准与强化外贸统计分析的题中之义。更多还原

【Abstract】 Using monthly export data of China Customs from 2001 to 2004,this paper studied the partial year bias of Sino-US trade statistic. Our results show that:( 1) Obvious differences among Chinese firms’ trade dynamics have been found during the sample period,and the average monthly proportion of the number of new firms engaged in trade has declined over time.( 2) Employing the calendar-year based statistics method to calculate the average annual trade growth rate and the annual average trade growth rate by month of Chinese firms,the former will be significantly overestimated,especially at the first period; whereas there will be both over-estimated and under-estimated partial year bias in the latter case,which is manifested as under-estimation in the first seven or eight months and over-estimation in the late three or four months.( 3) Using calendar year statistics method to estimate Chinese firms’ relative trade volume and trade growth rate,which will results in both under-estimation and over-estimation.( 4) After adjusting for the partial year bias in China’ s import and export growth,the contribution of extensive margin increased significantly,which suggests that the calendar year statistics method underestimates the role of extensive margin in the export growth. This study reveals that overlooking the partial year effects may easily lead to statistical illusions such as distortion of the trade index. In view of that,introducing corresponding correction methods and assessing its policy effect should be topics of improving statistical standard and strengthening statistics of international trade.更多还原