基于Meta分析的中国农业全要素生产率研究

STUDY ON THE CHINA’S AGRICULTURAL TOTAL FACTOR PRODUCTIVITY ESTIMATIONS BASED ON META-ANALYSIS

关键词:  农业全要素生产率  增长率  Meta分析  异质性  中国

Key words:  agricultural total factor productivity  growth rate  meta-analysis  heterogeneity  China

摘要:

目的 应用Meta分析方法，针对国内外中国农业全要素生产率测算研究的文献，探究其测算结果的一致性，以期为中国农业全要素生产率（TFP）的测算及其结果提供更为全面、客观、系统的认识与理解。方法 文章首先对中英文数据库中已发表的有关中国农业全要素生产率的文献进行检索筛选，再对纳入文献进行农业全要素生产率增长率的区域、方法、投入产出指标和年份区间的梳理，进而基于Meta分析定量化地分析各研究中农业全要素生产率增长率测算结果之间的异质性，并进行敏感性检验。结果 （1）中国农业TFP增长率测算总体异质性较低（I²=10%），剔除单独省份或地区作为研究区域的文献后，Meta分析结果异质性增大（I²=18%）；（2）投入指标方面，劳动力投入指标使用第一产业就业人数时的测算结果异质性较高（I²=61%），而使用农林牧渔业从业人数时，测算结果同质性显著（s=0）；（3）测算方法方面，使用DEA方法测算所得结果间同质性显著（I²=0）；（4）测算时段方面，各时段内农业TFP增长率测算结果呈现高度异质性，1992—1997年、1998—2003年、2004—2008年、2009—2015年各时段下I²结果分别为 94%、89%、68%、87%。结论 （1）1979—2015年我国农业全要素生产率年均增长2%是较为准确的测算结果，且单独省份的研究能够一定程度上填补以全国为研究区的文献间的异质性；（2）投入产出指标的遴选对农业TFP增长率测算结果有一定影响；（3）测算方法是农业TFP增长率异质性的主要来源；（4）农业TFP增长率测算中相关指标所选不变基期对长时间跨度测算结果影响不大，但对具体时段内的农业TFP测算结果影响显著。

Abstract:

In order to provide a comprehensive, objective and systematic understanding of China's agricultural growth, the meta-analysis approach was applied to examine the consistency of the results of China's agricultural total factor productivity (TFP) growth. Firstly, the published literature on agricultural TFP growth in both English and Chinese journals from the popular literature database was selected. Next, the agricultural TFP growth rate, as well as the calculated method, input and output indicators, time period, and covering regions in each literature was obtained and analyzed correspondingly. Lastly, the heterogeneity of the measured results of agricultural TFP growth rate was examined and the sensitivity was tested based on the meta-analysis approach. The results were showed as follows. (1) The overall heterogeneity of China's agricultural TFP growth rate was low（I²=10%）, however, the heterogeneity of the meta-analysis results increased after excluding the literatures that taking individual provinces or regions as research areas（I²=18 %）. (2) From the perspective of selecting the input-output indicators, the measured results were highly heterogeneous when the number of employees in the primary industry was used as the labor input indicator (I²=61%), while the measured results were significantly homogeneous when the number of employees in agriculture, forestry, animal husbandry and fishery was used for presenting labor input (I²=0). (3) From the perspective of calculating method, the results measured by data envelopment analysis (DEA) method had significant homogeneity (I²=0). (4) From the perspective of estimating time period, the results of agricultural TFP growth rate in different time intervals showed high heterogeneity. ) The overall heterogeneity of China's agricultural TFP growth rates (I²) results were 94%, 89%, 68% and 87% respectively for the time intervals of 1992—1997, 1998—2003, 2004—2008 and 2009—2015. The meta-analysis results proved that the reliable estimation result of China’s agricultural total factor productivity increased by 2% annually from 1979 to 2015. Meanwhile, the study of individual provinces can fill the heterogeneity compared when the whole country is the research area to a certain extent. Moreover, the selection of input-output indicators have a certain impact on the measured results of agricultural TFP growth rate. In addition, different estimating method is the main source of heterogeneity of calculating agricultural TFP growth rate. Besides, the constant base period of the relevant indicators in different studies plays a significant role in the heterogeneity of agricultural TFP measurement in a certain period of time, although it have little influence on the results of agricultural total factor productivity in a long run.