我国粮食生产的技术推进模式及影响机制研究

基于农业生产技术的功能性特征及随机前沿理论,构建可分离柯布-道格拉斯形式生产函数,测算我国粮食生产全要素增长率及其组成成分.实证结果表明,1999-2011年间,小麦、稻谷和玉米作物的全要素增长率普遍较低,其中,前沿技术进步率对全要素增长率具有正的贡献;但技术效率(尤其是M技术效率)在逐年降低,是造成全要素增长率偏低的主要原因.在此基础上,对影响我国粮食生产技术效率变化的因素进行理论分析和实证检验.研究发现,以直接补贴为主的农业财政支出政策对BC和M技术效率提高作用明显,且影响效果最强.粮食生产技术的推广与普及、粮食生产的规模化和专业化对技术效率具有显著正向影响,但市场机制的影响效果并没有显现出来.     

Quadratic data envelopment analysis

Data Envelopment Analysis (DEA) offers a piece-wise linear approximation of the production frontier. The approximation tends to be poor if the true frontier is not concave, eg in case of economies of scale or of specialisation. To improve the flexibility of the DEA frontier and to gain in empirical fit, we propose to extend DEA towards a more general piece-wise quadratic approximation, called Quadratic Data Envelopment Analysis (QDEA). We show that QDEA gives statistically consistent estimates for all production frontiers with bounded Hessian eigenvalues. Our Monte-Carlo simulations suggest that QDEA can substantially improve efficiency estimation in finite samples relative to standard DEA models.     

A graph efficiency multiproduct model of corn/livestock farming: Accounting for nitrate pollution

This paper estimates a non-parametric production frontier for a population of 117 corn/livestock farms in the Corn Belt region in 1987, employing a hyperbolic graph efficiency approach. There are 7 outputs, 39 variable inputs, 4 fixed inputs, and one bad input (residual nitrogen). Three graph efficiency models are estimated. A profit maximization model is specified to estimate a production frontier constrained only by the fixed factors. Two other models involving tax constraints are also estimated. One involves a tax directly on nitrogen and the other involves a tax directly on residual nitrogen, making the disposal of residual nitrogen costly. The nitrogen tax constraint is more effective in reducing residual nitrogen loadings and causes a larger reduction in income than the residual tax constraint.     

Determining rates of change in data envelopment analysis

This paper presents a general method for determining rates of change of outputs with respect to inputs along efficient facets of the Pareto-optimal frontier common to several empirical production possibility sets in Data Envelopment Analysis. As a prerequisite step, a theoretical analysis is provided for identifying the efficient facets. Non-negativity of these rates of change are discussed via ‘cone direction’ developments in both the input and output spaces.     

Identification of Pareto-efficient facets in data envelopment analysis

In Data Envelopment Analysis (DEA), identification of the Pareto-efficient frontier of an empirical production possibility set is a prerequisite step toward determining rates of change of outputs with changes in inputs along its piecewise linear facets. These rates of change, which will be different on different facets, have important economic and managerial implications in trade-off analysis, forecasting and resource allocation. Accurate and complete identification of the component members of each facet remains an open question. Such identification is important in certain procedures for determining these rates of change. This paper develops three modifications to the pivoiing criteria of the simplex algorithm, commonly used to solve DEA problems, as alternative strategies for more completely identifying facet members of the Pareto-optimal frontier common to several production possibility sets in DEA. Experimental results from implementing these strategies are presented.     

Equivalences between Data Envelopment Analysis and the theory of redundancy in linear systems

This paper establishes how the non-parametric frontier estimation methodology of Data Envelopment Analysis (DEA) and the classical problem of detecting redundancy in a system of linear inequalities are connected. We present an analysis of the sets generated in two of DEA's models from where the empirical efficient production frontier is established from the point of view of polyhedral set theory. This yields convenient alternative characterizations of these sets which provide new insights about their properties. We use these insights to show how these polyhedral sets connect DEA to redundancy in linear systems. This means that DEA can benefit from a rich and well-established collection of computational and theoretical results which apply directly from redundancy in linear systems.     

Choices and intervals

We consider a random interval splitting process, in which the splitting rule depends on the empirical distribution of interval lengths. We show that this empirical distribution converges to a limit almost surely as the number of intervals goes to infinity. We give a characterization of this limit as a solution of an ODE and use this to derive precise tail estimates. The convergence is established by showing that the size-biased empirical distribution evolves in the limit according to a certain deterministic evolution equation. Although this equation involves a non-local, non-linear operator, it can be studied thanks to a carefully chosen norm with respect to which this operator is contractive.     

中国经济随机前沿模型效率的贝叶斯统计推断

基于扩展的随机生产前沿模型,研究了区域生产效率的差异和其影响因素的作用效果,应用贝叶斯统计方法对中国各省份2010-2017的年度数据(不包含港澳台地区,下同)进行了实证研究.研究发现:生产效率总体呈逐渐下降的趋势,地区间生产效率有一定的差异,高等教育规模对生产效率具有显著的直接影响.人力资本能有效促进东部和中部地区的经济增长,西部地区主要依靠资本促进经济增长.环境污染对中部地区的经济增长具有一定的负向作用.     

转型期中国工业全要素生产率与效率——基于细分行业的随机前沿模型分析

本文利用1996-2007年我国工业36个细分行业的面板数据,通过建立随机前沿模型,测算了转型期我国工业及其细分行业的全要素生产率,以及其分解要素的波动情况。实证研究表明,1996-2007年我国TFP平均为4.76%,并呈逐步上升趋势;TFP提高的主要原因是技术进步,平均来说,TFP增长的85.50%来源于技术进步的贡献;因为技术效率的提高使TFP平均每年提高了0.94个百分点;资源配置效率的提高对TFP的贡献年平均0.52个百分点,并有较大的波动;而因为规模总报酬递减的影响,TFP每年反而下降了0.78个百分点。通过经济增长来源分析,我国工业经济增长由主要靠资本驱动逐渐向靠技术创新驱动转变,转型期经济增长方式已表现为集约型。     

Consistency of returns-to-scale characterizations of production frontiers with respect to model specification

Returns-to-scale (RTS) characterizations and the underlying notion of scale elasticity are important characteristics of production frontiers, in both parametric and nonparametric methodologies of efficiency and productivity analysis. In practical applications of these methodologies, the model of technology is often experimented with and modified before it is finalized, which involves, for example, a change of the data set, incorporation, exclusion or aggregation of inputs and outputs, or experimentation with the production assumptions, or axioms, on which the model is based. While it is well-known how such modifications of technology affect the efficiency scores, their effect on the RTS characterization of the production frontier has not been sufficiently explored in the literature. In this paper we obtain several general results that clarify this issue.     

只有产出(投入)BC~2模型中决策单元效率的几何刻画

在DEA方法中,DEA有效和弱DEA有效的决策单元位于生产前沿面上,非弱DEA有效的DEA无效决策单元位于生产可能集的内部而非生产前沿面上.通过引入生产可能集与生产前沿面移动的思想,证明只有产出(投入)的BC²模型评价下的决策单元的最优值与相应的生产前沿面的移动值存在倒数关系,以双产出(投入)情形图示说明,明确了决策单元在生产可能集中所处的位置.     

On the inconsistency of the Malmquist–Luenberger index

Apart from the well-known weaknesses of the standard Malmquist productivity index related to infeasibility and not accounting for slacks, already addressed in the literature, we identify a new and significant drawback of the Malmquist–Luenberger index decomposition that questions its validity as an empirical tool for environmental productivity measurement associated with the production of bad outputs. In particular, we show that the usual interpretation of the technical change component in terms of production frontier shifts can be inconsistent with its numerical value, thereby resulting in an erroneous interpretation of this component that passes on to the index itself. We illustrate this issue with a simple numerical example. Finally, we propose a solution for this inconsistency issue based on incorporating a new postulate for the technology related to the production of bad outputs.     

The influence curve approach in data envelopment analysis

The behavior of efficiency in the stochastic DEA model is examined here in terms of the influence curve approach which quantifies the influence of observed data on the empirical fit of the production frontier. Data influence is analyzed here through robustness. Two types of robustness and sensitivity issues are analyzed here in terms of (a) a new class of minimax measures, and (b) a set nonlinear efficiency measures and it is shown through empirical applications that in suitable cases these measures outperform the conventional ones.This is a revised version of an invited paper presented at the 13th International Symposium on Mathematical Programming held in tokyo, Japan, 29 August 2 September 1988. Sincere thanks are due to Professors A. Charnes and J. Sojka for their valuable comments and suggestions. Thanks are also due to the Guest Editor S. Shinoda and the two anonymous referees for their comments.     

中国粮食生产技术效率的实证研究——随机前沿面生产函数的应用

本文使用我国1992、1995年和1999年三年的县(市)级数据,采用超越对数随机前沿面生产函数,研究了我国粮食生产技术效率的空间分布和影响因素。发现:(1)技术效率在地理空间上的分布是不均衡的,呈现出南高北低的格局:(2)从92年到99年,全国平均技术效率大约下降1%,且效率分布的变异性似乎有加大的趋势;(3)农业生产的自然条件和一些社会经济因素对粮食生产的技术效率有着显著的影响。     

The case for the use of multiple imputation missing data methods in stochastic frontier analysis with illustration using English local highway data

Multiple imputation (MI) methods have been widely applied in economic applications as a robust statistical way to incorporate data where some observations have missing values for some variables. However in stochastic frontier analysis (SFA), application of these techniques has been sparse and the case for such models has not received attention in the appropriate academic literature. This paper fills this gap and explores the robust properties of MI within the stochastic frontier context. From a methodological perspective, we depart from the standard MI literature by demonstrating, conceptually and through simulation, that it is not appropriate to use imputations of the dependent variable within the SFA modelling, although they can be useful to predict the values of missing explanatory variables. Fundamentally, this is because efficiency analysis involves decomposing a residual into noise and inefficiency and as a result any imputation of a dependent variable would be imputing efficiency based on some concept of average inefficiency in the sample. A further contribution that we discuss and illustrate for the first time in the SFA literature, is that using auxiliary variables (outside of those contained in the SFA model) can enhance the imputations of missing values. Our empirical example neatly articulates that often the source of missing data is only a sub-set of components comprising a part of a composite (or complex) measure and that the other parts that are observed are very useful in predicting the value.     

Efficiency measurement in the stochastic frontier model

Deterministic models of technical efficiency assume that all deviations from the production frontier are due to inefficiency. Critics argue that no allowance is made for measurement error and other statistical noise so that the resulting efficiency measure will be contaminated. The stochastic frontier model is an alternative that allows both inefficiency and measurement error. Advocates argue that the stochastic frontier models should be used despite other potential limitations because of the superior conceptual treatment of noise. As will be demonstrated in this paper, however, the assumed shape of the error distributions is used to identify a key production function parameter. Therefore, the stochastic frontier models, like the deterministic models, cannot produce absolute measures of efficiency. Moreover, we show that rankings for firm-specific inefficiency estimates produced by traditional stochastic frontier models do not change from the rankings of the composed errors. As a result, the performance of the deterministic models is qualitatively similar to that of the stochastic frontier models.     

Measuring the efficiency of forest districts with multiple working circles

Data envelopment analysis (DEA) is a methodology extensively applied to measuring the relative efficiency of decision making units with multiple inputs and multiple outputs. Herein, a DEA model is developed to measure the efficiency of forest districts which are divided into a number of subdistricts called working circles (WCs). The idea is to construct district production frontiers from the WCs of individual districts. Superimposing the district production frontiers of different districts one derives the forest production frontier. The closeness of a district production frontier to the forest production frontier indicates this district's efficiency. As an illustration, the developed model measures the eight districts, with a total of thirty-four WCs, of the national forests of the Republic of China on Taiwan. The results provide the top management with an idea of how far each district can be expected to improve its performance when compared with other districts.     

Group-specific stochastic production frontier models with parametric specifications

This paper develops a stochastic frontier model that not only focuses more on group-specific temporal variations in technical efficiency rather than individual temporal variations, but also allows for a parametric function of the time-varying coefficient of the efficiency factor. We derived the concentrated least squares estimator and its asymptotic properties. When applied to the Penn World data set, the group-specific models yield much more variation in the temporal patterns of efficiency across countries. This application demonstrates the feasibility of applying a group-specific stochastic frontier model with a parametric function of temporal pattern to a real empirical analysis.     

On the Production of Sound by Turbulent Boundary Layer Flow over a Compliant Coating

A theory is proposed of the generation of sound by turbulentboundary layer flow over a nominally plane, compliant wall coating.It is argued that, at sufficiently low mean flow Mach numbers,the principal noise production mechanism involves the scatteringof energy into sound from the hydrodynamic region of the wallpressure fluctuations by time dependent irregularities in thefree surface of the coating induced by the turbulent flow. Theeffective noise sources are equivalent to a distribution ofaerodynamic dipoles over the surface of the coating whose axesare parallel to the wall. The far field acoustic pressure spectrum,and the wavenumber-frequency wall pressure spectrum in the acousticdomain are expressed in terms of the behaviour of the wall pressurespectrum in the hydrodynamic domain. A simple empirical modelof the hydrodynamic region, defined in terms of measurable parameters,is used to obtain explicit representations of the acoustic spectra.     

二阶段加法DEA模型的生产可能集与生产前沿面

针对二阶段加法DEA模型的中间要素的特殊性,构造生产可能集及其公理体系,由此定义生产前沿面,并建立DEA有效和生产前沿面之间的等价关系.通过构造一个多目标规划模型,建立该问题的Pareto有效解与DEA有效之间的等价关系.