Estimating technical efficiency under unobserved heterogeneity with stochastic frontier models: application to northern German dairy farms

This article uses panel data estimation techniques to examinetechnical efficiency of individual dairy farms in northern Germany.To the extent that agricultural production is characterisedby heterogeneous production conditions, estimation techniquesthat do not account for unobserved heterogeneity produce biasedefficiency estimates. We therefore estimate a number of conventionalpanel data models and Greene's recently proposed ‘true’random-effects model, as well as an extension of the model toascertain the effects of different specification on the productionfunction and efficiency estimates. Our results appear to supporttheoretical expectations and previous findings according towhich a specification that is both time-variant and also controlscorrelations between unobserved heterogeneity and the explanatoryvariables avoids heterogeneity bias and thus ensures consistentefficiency estimates.     

Patterns in Technical Efficiency and Technical Change at the Farm‐level in England and Wales, 1982–2002

English and Welsh farm‐level survey data are employed to estimate stochastic frontier production functions for eight different farm types (cereal, dairy, sheep, beef, poultry, pigs, general cropping and mixed) for the period 1982 to 2002. Differences in the relative efficiency of farms are explored by the simultaneous estimation of a model of technical inefficiency effects. The analysis shows that, generally, farms of all types are relatively efficient with a large proportion of farms operating close to the production frontier. However, whilst the frontier farms of all types are becoming more efficient through time because of technical change, it is also the case that the efficiency of the average farm for most farm types is increasing at a slower rate. In addition, annual mean levels of efficiency for most farm types have declined between 1982 and 2002. The factors that consistently appear to have a statistically significant effect on differences in efficiency between farms are: farm or herd size, farm debt ratios, farmer age, levels of specialisation and ownership status.     

The Contribution of Unmeasurable Inputs to Fisheries Production: An Analysis of Technical Efficiency of Fishing Vessels in the English Channel

Variations in the efficiency of demersal trawlers operating in the English Channel were examined through the estimation of a stochastic frontier production function. The most important measurable factor affecting efficiency was the age of the vessel. However, unmeasurable factors accounted for about 65% of the variation in efficiency, and as much as 9% of the total variation in catches between boats. It is postulated that most of this variation was due to differences in skipper and crew skill. In contrast, "luck" accounted for around 11% of the variation in catches between boats.     

我国玉米产业生产技术效率与其影响因素研究——基于2001～2011年的省级面板数据

土地、环境等资源制约与农村劳动力日益短缺等问题都使得我国粮食安全更为棘手。突破目前土地生产率提高缓慢,劳动生产率水平普遍较低的局面,是保障我国粮食产业稳定健康发展的根本出路和必要前提。土地生产率的提高主要依靠生物化学型的要素投入,而劳动生产率的提高则需要农业机械化率水平的提高,所以两种类型的技术投入是影响粮食增产增收的根本来源。文章采取随机前沿生产函数超越对数面板模型,对2001~2011年的全国省级玉米生产的技术效率和非技术效率影响因素进行了测算和分析,并进一步通过面板数据的回归模型分析了技术效率与生物化学型及机械型技术投入之关系。结果表明:我国玉米生产总体技术效率水平较高,其中东南部地区要优于中西部地区;自然灾害、政策补贴及地域差异都会对非技术效率造成显著影响;生物化学型要素投入对生产的技术效率贡献突出,是当前以及未来玉米增产的主要手段。     

Heterogeneity of Long‐run Technical Efficiency of German Dairy Farms: A Bayesian Approach*

In parametric efficiency studies, two alternative approaches exist to provide an estimate of the long‐run efficiency of firms: the dynamic stochastic frontier model and the generalised true random‐effects model. We extend the former in order to allow for heterogeneity in the long‐run technical efficiency of firms. This model is based on potential differences in firm‐specific characteristics and in firms’ inefficiency persistence. The model is applied to an unbalanced micro‐panel of German dairy farms over the period 1999 to 2009. Estimation of long‐run technical efficiency and inefficiency persistence is based on an output distance function representation of the production technology and estimated in a Bayesian framework. The results suggest that heterogeneity in long‐run technical efficiency of farms is mostly attributed to discrepancies in farm‐specific factors rather than differences in farms’ inefficiency persistence. Farm size is positively related to long‐run technical efficiency while subsidies exert a negative effect on the long‐run technical efficiency of farms. Inefficiency persistence is found to be very high, but heterogeneity in this persistence is low.     

Decomposition of Productivity Growth Using Distance Functions: The Case of Dairy Farms in Three European Countries

Within an output distance function framework, the Total Factor Productivity growth index is decomposed into four components (technical change, technical and allocative efficiency, and scale component). We estimate stochastic translog output distance functions using panel data from dairy farms over the period 1991–94 for three European countries (Germany, the Netherlands, and Poland). Results indicate that the change in the productivity growth index in Germany (+6%) and Poland (−5%) are mainly dictated by the technical change component. In contrast, the productivity growth index in the Netherlands (+3%) is influenced by allocative efficiency components.     

渔船作业效率及政策研究

本文使用随机前沿生产模型研究了沿海某市渔船的作业效率,结果显示:抽样渔船的平均作业效率只有33%;渔船出海频率过高和性能落后是导致其效率低下的主要原因;船员工资的增加则提高了生产效率。为了提高渔船作业效率,建议采取以下措施:保持和增加资源存量,进一步降低捕捞强度,提高渔船的准入门槛、进行技术扶持、引入外部资金以及帮助渔民转产转业等。     

Urban Influence on Costs of Production in the Corn Belt

This article determines the relative technical efficiency of rural- and urban-influenced crop/livestock enterprises in the Corn Belt. Farmers in urban-influenced locations are less technically efficient than farmers in rural locations. During 1998–2000, stochastic production frontier procedures indicate that a 10% increase in urban influence leads to a close to 4% decrease in technical efficiency. The most successful urban-influenced farms have controlled costs as effectively as rural farms. They have tended to de-emphasize that nondairy livestock activities—particularly beef and hogs—do not rely extensively on off-farm income, and have relatively large, less residential/lifestyle operations compared to less successful urban-influenced farmers. However, our statistical analysis clearly bears out the refrain in popular literature that urban proximity raises the cost for, and decreases the viability of, traditional farms.     

林业技术效率及其影响因素研究——基于随机前沿生产函数

文章运用随机前沿生产函数估计了林业生产投入要素劳动力和资本的产出弹性,测量了各省区2002～2009年的林业技术效率,并分析了林业技术效率的影响因素。结果表明:林业产业存在明显的技术效率损失,随机前沿生产函数的误差主要是由技术非效率引起;林业产业劳动力和资本的产出弹性分别为0.58和0.47,林业生产仍处于规模报酬递增阶段。总体上,各省区林业技术效率水平相差不大,且林业的平均技术效率水平呈现缓慢上升的趋势;森林病虫鼠害的发生率显著降低了林业技术效率,而基层林业工作站人员文化水平的提高能有效的改善林业生产的技术效率。     

社会资本对桃农生产技术效率的影响及对策研究——基于陕西省铜川市桃业的调查

利用铜川地区桃农调研数据,构建随机前沿生产函数模型,将社会资本各维度加入技术效率损失项,测算桃农生产技术效率水平,分析社会资本对桃农生产技术效率的影响。结果表明:桃农的平均生产技术效率为79.38%,存在着一定程度的技术无效率;在社会资本各维度中,关系网络,集体行动以及信息交流的改善能够显著提高桃农生产技术效率,而干群关系、信任与团结对桃农生产技术效率的影响未通过显著性检验。因此,改善桃农关系网络,集体行动,信息交流状况,是提高桃农生产技术效率的有效途径。     

茶农生产性投资的技术效率及其影响因素实证分析——以福建安溪为例

以福建省安溪县茶农问卷调查数据为基础,利用随机前沿生产函数模型估计样本茶农投资的技术效率,并分析技术效率的变化规律及其影响因素。研究表明,茶农从事茶叶生产加工的时间、茶农从事茶叶生产加工的时间的平方项、茶农户主的受教育年限这3个解释变量对于技术效率的影响不显著;而茶农户主年龄、茶农主栽品种、是否接受过培训、茶农茶叶收入占家庭总收入的比例、茶农家庭拥有的茶园面积、村庄所在地类型虚变量与技术效率呈现正相关的关系;茶农家庭拥有的茶园面积的平方项、地区差异则对技术效率产生负向影响。