Predictive performance of the World Bank's commodity price projections

The World Bank's commodity price projections are widely used for various planning purposes. Two aspects of the Bank's projections of relative prices are studied in this paper. The first is whether the forecasts make efficient use of the information available at the time the forecast is made. The second is whether the forecasts predict future prices with greater accuracy than alternative forecasting methods. These matters are studied by comparing the World Bank's past price projections with the actual prices that were subsequently observed. The results show that, overall, the World Bank forecasts do not pass either test. First, the World Bank forecasts are informationally inefficient. Prediction error (projection minus actual price) tends to be positively correlated with the projections themselves. Although the direction of future price movements tends to be correctly predicted, the magnitude of these movements tends to be overpredicted. Second, the World Bank forecasts do not perform well even compared with the simplest of alternative forecasting methods - the prediction of no change.     

A CROSS-COMMODITY APPRAISAL OF DEMAND-RAISING RESEARCH BENEFITS: PORK AND CHICKEN IN AUSTRALIA

A multi-commodity model is developed for evaluating the gains from research which raises the demand for a commodity, and applied to the pig and chicken industries in Australia. The major finding is that the gain to pork producers is larger, and the gain to consumers smaller, with a cross-commodity consideration than without. Bigger differences in results are observed with larger values of the cross-price elasticity between pork and chicken, and with a larger shift in demand for chicken. However, the aggregate benefits to the Australian pig industry are not significantly affected by price changes in the market for chicken. The implication of the analysis is that, by ignoring the cross-market feedback between commodities closely related in consumption, consumers (or taxpayers) of the commodity experiencing a rise in demand may bear a higher-than-optimal outlay on public research directed to increasing the demand for that commodity.     

新型合作农场：经济发达地区农地规模经营的逻辑与实践

目的 当前,“谁来种地”成为农业发展面临的重要问题。近年来部分经济发达地区出现的、由村级集体经济组织主导的新型合作农场成为创新农业经营组织形式、发展农地规模经营的新探索,对其实践与逻辑进行探讨有一定的必要性和现实意义。方法 文章运用案例分析法,以海门新型合作农场为例,从新制度经济学视角对新型合作农场的农业经营体制创新特征进行分析,并与其他新型农业经营主体进行对比,指出新型合作农场在联农带农、壮大村集体经济方面的优势。结果 新型合作农场将村集体经济组织实体化为农地经营主体,整合土地、劳动力、资本、技术等资源要素,并将现代经营管理制度引入农业生产,在土地规模经营的同时有效实现了产权明晰、交易成本降低、风险分担和外部性内部化,有效促进了农民和村集体的双增收,实现了农业生产的帕累托改进。结论 新型合作农场充分做实了村集体“统”的功能,其合作化、一体化、企业化的经营模式可以为我国其他地区农地适度规模经营提供一种思路和参照。     

THE IMPORTANCE OF PRODUCED MEANS OF PRODUCTION IN UK AGRICULTURE

Neoclassical production theory assumes that outputs and inputs can be separated into two distinct commodity groups. However, this fails to take account of the presence of produced means of production in agriculture which undermine the ceteris paribus assumption on which partial equilibrium analysis is based-a criticism identified as part of the broader Sraffian critique of neoclassical economics. A simulation exercise designed to investigate the importance of produced inputs in UK agriculture found evidence of perverse aggregate supply response resulting from the use of feedgrain, an output from the cereal sector, as a produced input in the livestock sectors. This empirical result lends some support to the Sraffian analysis; however, it is suggested that the perversity arises from failure to take account of the produced input, and that computing ‘net output’     

Effects of Geographical Stratification in a Farm Accountancy Data Network on the Accuracy of the Estimates

This study analyses the effects on the accuracy of the estimates produced by an additional stratification of a sample, in this case the sample of the Farm Accountancy Data Network (FADN) of Navarra. This is carried out by studying the accuracy of the total standard gross margin estimator. For the analysis, the variances of the estimator were compared for two samples: one stratified according to type of farming and economic size, and the other with the addition of a geographical stratification. The conclusion of the analysis is that for samples whose size is similar to that of the FADN of Navarra (400 farms), accuracy is not improved by a geographical stratification. This result, a particular case in which stratification does not improve the accuracy of the estimates, may be clarified by the theoretical considerations expounded in this paper.     

How Reliable Are Hog Futures as Forecasts?

The Chicago Mercantile Exchange hog futures contract was revamped in 1997 and it is one of the largest futures markets for a nonstorable commodity. The literature is divided on whether or not futures prices for nonstorables provide reliable forecasts of cash prices. We find that from 1998 to 2004, the hog futures market was an unbiased predictor of cash prices.     

SOME ILLUSTRATIONS OF CHAOS IN COMMODITY MODELS

This paper develops three commodity models which exhibit chaotic behaviour. The examples chosen are a demand system and two cobweb supply and demand models. The latter differ from the standard forms in that they include risk aversion and a new specification for the formation of price expectations. Simulation of the model highlights three implications of chaos: such systems generate complex time-paths even if the exogenous variables within the model are held constant; the simulated time path is critically sensitive to the starting value of variables, and parameter values; and the average behaviour of the system is critically sensitive to parameter and exogenous variable values. ‘Critically sensitive’ means that very small changes in parameter or starting values leads to substantial changes in the time paths of the variables in the model. These results suggest that if real commodity sectors can be characterised as chaotic systems, then the ability to conduct forecasting and policy analysis of such sectors will be severely curtailed.     

Evaluation of USDA Interval Forecasts of Corn and Soybean Prices

USDA World Agricultural Supply and Demand Estimates (WASDE) price forecasts are published as an interval, but are typically analyzed as point estimates. Thus, all information about uncertainty imbedded in the forecast is ignored. The purpose of this article is to evaluate the accuracy of WASDE corn and soybean price forecasts using methodology suitable for testing judgmental interval forecasts. Accuracy tests suggest that WASDE forecasts are not calibrated at the 95% confidence level for both commodities and generally not calibrated for corn, but calibrated for soybeans, at the implied confidence level elicited from the survey of forecast providers.     

环京津地区农产品物流发展现状与对策

随着网络电商行业的兴起与不断壮大,农产品贸易在其中扮演着什么样的角色?"互联网+"时代,农产品是否可以找到一条新的出路?文章通过对农产品的产品特性分析、对环京津地区的经济现状概述、对农产品现代物流产业的发展趋势介绍,运用SWOT分析法解析环京津地区农产品物流的优势、劣势、机会、威胁;运用PEST分析法剖析环京津地区政治、经济、文化、技术等宏观环境因素,找出现阶段农产品物流发展中出现的问题,提出立足环京津地区构建三方物流平台的建议。     

COMPARATIVE FORECAST ACCURACY IN THE NEW SOUTH WALES PRIME LAMB MARKET

The market for Australian prime lamb is characterised by high production seasonality and a highly competitive retail demand. Because these factors often translate into substantial market variability, regular forecasts of supply and demand are important requirements of lamb market participants. There has been some forecasting activity in the state and national lamb markets but it has been a somewhat controversial activity. This paper assesses the comparative forecast accuracy of a range of methods in the New South Wales lamb market. The results indicate that no single method is clearly superior in all situations and the greatest scope for improving forecast accuracy in the New South Wales lamb market is through the use of combined econometric and naive approaches.     

The Influence of Commodity Programs on Acreage Response to Market Price: With an Illustration Concerning Rice Policy in the United States

Farm programs influence the parameters of typically estimated supply functions. We develop and apply an approach that uses detailed information about farm program incentives and constraints to identify underlying structural acreage response parameters when the data reflect behavior under complex government commodity programs. We illustrate the approach with data on rice acreage response to market price in the United States. For U.S. rice, estimates that fail to appropriately incorporate the program rules under which market data were generated are three to four times smaller than the structural parameters that are useful for most policy analysis or projections under alternative policies.     

THE SOURCES OF COMMODITY EXPORT REVENUE VARIABILITY IN THE SOUTH PACIFIC ISLAND NATIONS

Using annual time-series data for the selected South Pacific Island Nations (SPINs), sources of commodity export revenue variability (CERV) are analysed using forecast error decomposition and impulse response analysis based on vector autoregression (VAR) models. The evidence shows that there are different sources which contribute to CERV, although the magnitudes of the contributions are variable. External market factors are important, but it is shown that domestic factors (especially the GDP) have equal if not greater influence on CERV in the selected SPINs, particularly in Solomon Islands and Fiji.     

ECONOMIC EVALUATION OF THE FARM WOODLAND SCHEME IN SCOTLAND

This paper describes an economic evaluation of planting under the Farm Woodland Scheme in Scotland based on the calculation of the Scheme's net UK Exchequer cost (NEC) and its relationship to the benefits observed through a survey of first-year Scheme entrants. It was found that the motivation in planting was primarily for ‘environmental’ benefits such as landscape, amenity, wildlife and sport. Income and timber production were much less important. On average, payments under the Scheme under-compensated farmers for their direct and opportunity costs associated with planting. When based on agricultural savings in the year of planting, the annual NEC was #58 per ha, but this cost increases substantially if the additionality principle is applied. Anticipated benefits in terms of farm output reduction, income diversification, employment and timber production are identified but the effects are not large. Environmental benefits were not included in the evaluation and these may provide greater justification for the expenditure.     

信阳市乡村旅游资源调查及潜力分析

［目的］通过对信阳市旅游资源进行调查及潜力分析,为信阳市乡村旅游资源的合理开发利用提供科学指导,发展其乡村旅游产业,提高农村居民收入,促进信阳市新农村建设。［方法］文章以信阳市乡村旅游资源为调查研究对象,采用层次分析法（AHP）对其乡村旅游资源潜力进行分析,构建信阳市乡村旅游资源潜力分析指标体系,并计算各指标权重,通过游客问卷调查的方式获取信阳市乡村旅游资源潜力分析指标重要性的打分值（分值范围为1~ 10）权重值和打分值的乘积为最终得分,按最终得分对各指标因素进行重要性排序,据此分析信阳市乡村旅游资源潜力。［结果］(1)在指标体系中,系统层乡村旅游资源权重值最高,旅游开发次之,乡村环境最低。(2)在乡村旅游资源中,特色饮食权重值最高,村落建筑权重值最低。（3）在乡村环境中,治安环境权重值最高,基础设施权重值最低。（4）在旅游开发中,交通便利性权重值最高,纪念商品的权重值最低。（5）各指标因素的重要值排序可以看出,特色饮食、山水景色、田园风光、文化艺术等旅游资源相关因素重要值均较高,而食宿服务、服务人员素质、宣传活动、旅游项目开发、纪念商品等与旅游开发相关的因素重要值均较低。［结论］信阳市具有丰富的乡村旅游资源,但缺乏科学的开发利用,具有较大发展潜力。     

新疆棉花生产性废弃物处理方式的影响因素分析

建立农业可持续发展长效机制是推进生态文明建设的重要任务,也是解决"三农"问题的重要使命,农业面源污染问题日渐成为建立农业可持续发展长效机制的严峻挑战。新疆是全国最大的优质商品棉生产基地,其棉花种植占中国棉花种植面积近一半,棉花生产在有力促进新疆地区收入增加的同时其负外部性也日渐显现,农膜、农药瓶及化肥包装物等生产性废弃物随意处理现象突出,新疆已成为"白色污染"最严重的区域,如何无害化处理这些废弃物,具有十分重要的现实意义。文章为研究新疆棉花生产性废弃物的处理方式及其影响因素,基于对新疆玛纳斯县、呼图壁县、石河子市、莎车县、阿瓦提县及哈密市276家农户的调查数据,探讨农户对农膜、农药瓶及化肥包装物等农业生产性废弃物处理方式的选择,并运用Logistic回归模型分析其影响因素。研究结果表明:棉农的受教育程度、棉花种植面积的大小、参与棉花专业合作社对于棉农对这些废弃物处理方式的选择具有正向作用,而棉农环保意识的高低没有转化成为其决策的重要因素。在此研究结论基础上,给出了有利于改善棉农生产性废弃物处理方式的几点启示。     

OVER-REACTIONS IN US AGRICULTURAL COMMODITY PRICES

The purpose of this paper is to test rationality in agricultural commodity markets. We investigate the price-adjustment process after significant events using abnormally large cash commodity price changes as proxies for the arrivals of significant events in the markets. The evidence suggests that market rationality is violated. Generally, agricultural commodity prices tend to reverse after significant events. This is consistent with the over-reaction hypothesis which maintains that traders in spot commodity markets over-weight more recent information and under-weight prior information in their expectations.     

SOME FEATURES OF FARM INCOME AND STRUCTURE VARIATIONS IN REGIONS OF THE UNITED KINGDOM

Farm income trends and developments in farm structure have varied within the UK in the last decade. While Wales and Northern Ireland have similarities in form structure, agricultural production has risen to a much smaller extent, and farmers have suffered more severe net income reductions, in Scotland and Northern Ireland than in England and Wales. The net incomes of Cropping farms rose faster and, in England, have remained much higher than those of Dairy or Livestock farms. Large numbers of small farm businesses depend on beef cattle and sheep production and have limited development prospects. As most of their occupiers are unlikely to find other employment, structural problems will persist and policy adjustments are suggested to enable agriculture to contribute more to the economy in remote and depressed localities.     

A REVIEW OF THREE RESEARCH PROGRAMS IN QUANTITATIVE MODELLING IN THE BUREAU OF AGRICULTURAL ECONOMICS*

Elements of three of the BAE's research programs in economic modelling of the rural sector, namely, the modelling of agricultural production systems, rural commodity markets and agriculture within a general equilibrium framework, are reviewed with emphasis on the use of such models in policy work. Suggestions are made for further modelling in these areas.     

CHANGES IN THE TERMS OF TRADE FOR AGRICULTURE: NEW PLATEAU OR NEW PRECIPICE*

This paper looks at the recent boom in agricultural commodity prices to see to what extent the changes these prices reflect are of a structural rather than short term nature. It concludes that they are essentially short term: a lagged supply response to the agricultural depression of 1970 and 1971; the coincidence of normal commodity cycles for several commodities; an unusual coincidence of adverse seasonal conditions in major producing areas, particularly the U.S.S.R.; and an unprecedented upswing in world economic activity. Nevertheless, there are a number of factors which suggest that, other than possibly in short term disequilibrium situations, agricultural commodity prices will not decline to previous levels: worldwide inflation; redirection in world agricultural support policies; and the energy crisis. Many of these factors win also influence prices of manufactured goods and hence the terms of trade. After considering the problems of world food supplies and continued growth in world population, the paper suggests that there is little evidence of a major structural change in the market for agricultural commodities. Rather, it points to a return to the previous situation where there is a slight tendency for the terms of trade to move against agriculture.