Impacts of Market Reform on Spatial Volatility of Maize Prices in Tanzania

Maize is one of the major staples and cash crops for many Tanzanians. Excessive volatility of maize prices destabilises farm income in maize‐growing regions and is likely to jeopardise nutrition and investment in many poor rural communities. This study investigates whether market reform policies in Tanzania have increased the volatility of maize prices, and identifies regional characteristics that can be attributed to the spatial price volatility. To achieve the objectives, an autoregressive conditional heteroskedasticity in mean (ARCH‐M) model is developed and estimated in this study. Results show that the reforms have increased farm‐gate prices and overall price volatility. Maize prices are lower in surplus and less developed regions than those in deficit and developed regions. Results also show that the developed and maize‐deficit regions, and regions bordering other countries have experienced less volatile prices than less developed, maize‐surplus and non‐bordering regions. Our findings indicate that investments in communication and transportation infrastructures from government and donor countries are likely to increase inter‐regional and international trade, thereby reducing the spatial price volatility in Tanzanian maize prices in the long run.     

Posted Prices and Bid Affiliation: Evidence from Experimental Auctions

In most experimental auctions, researchers ask participants to bid on the same item in multiple potentially binding rounds, posting the price submitted by the top bidder or bidders after each of those rounds. If bids submitted in later rounds are affiliated with posted prices from earlier rounds, this practice could result in biased value estimates. In this article, we discuss the results of an experiment designed explicitly to test whether posted prices affect bidding behavior. We find that for familiar items, high posted prices lead to increased bids in subsequent rounds. Our results have implications for researchers conducting experimental auctions.     

Decomposing Changes in Agricultural Producer Prices

This article develops a method for decomposing changes in agricultural producer prices. The method builds on a procedure used by the World Bank, with the main variables in the decomposition being trade prices, exchange rates and trade policies. We expand on the World Bank decomposition procedure by broadening the analysis of policy effects, adding the effect from incomplete transmission of changes in trade prices and exchange rates to producer prices, and handling the effect on prices from interactions between variables as they change simultaneously. Decomposition results are presented for various commodities for the major emerging markets of Brazil, China and South Africa.     

Monetary Impacts and Overshooting of Agricultural Prices in an Open Economy

This article's focus is on the time adjustment paths of the exchange rate and prices in response to unanticipated monetary shocks. First, we expand the theoretical specification of the overshooting hypothesis by generalizing Dornbusch's model to include a third sector (i.e., agricultural prices). Second, we employ Johansen's cointegration test along with a vector error correction model to investigate whether agricultural prices overshoot in an open economy. The empirical results indicate that agricultural prices adjust faster than industrial prices to innovations in the money supply, affecting relative prices in the short run, but strict long-run money neutrality does not hold.     

粮食、食品价格和CPI的VAR实证研究

综述了目前国内关于粮食价格、食品价格对CPI的影响机制的研究.选取2001年7月至2012年12月的月度数据,通过VAR进行了粮食冲击效应分析,采用Johansen检验进行了三者因果的验证,合理解释了食品价格和粮食价格、CPI三者之间的影响关系.结论：在研究的时间段中,粮食价格和食品价格的增长都会引起物价水平的增长;物价水平的上涨也会影响到粮食价格.但是,物价水平对食品价格、粮食价格对食品价格的变化却影响不明显.     

Commodity Prices and Unit Root Tests

Price theory suggests that commodity prices should be stationary series. Yet, tests for unit roots rather frequently imply that these prices are not stationary. This seeming inconsistency is investigated by applying alternative specifications of unit root tests to prices of corn, soybeans, barrows and gilts, and milk. The preponderance of evidence suggests that nominal prices do not have unit roots, but the results are sensitive to the specification of the test equation. Accounting for a structural change that shifts the mean appears to be an important issue in unit root tests.     

国内外橡胶价格的动态关系分析

运用协整分析、格兰杰因果检验、脉冲响应函数等计量方法,使用1997年1月到2009年12月国内天然橡胶橡胶、国内合成橡胶、国际天然橡胶的月平均价格数据,研究了各类价格之间的动态关系。研究结果表明:国内天然橡胶、合成橡胶与以人民币计价的天然橡胶国际价格存在长期均衡关系,但与美元计价的价格则不存在;国内天然橡胶价格偏离时受其与国际市场的长期均衡的调整力强,国内天然橡胶和合成橡胶的均衡调整对后者的调整作用更大;天然橡胶国际市场价格对国内天然橡胶和合成橡胶价格都有较强的预测力,国内合成橡胶价格对天然橡胶价格具有预测力,反之,预测力很弱;国际天然橡胶价格变动对国内天然橡胶和合成橡胶的冲击大,尤其是对前者,但国内价格变动对国际价格的冲击力小;国内天然橡胶价格对来自合成橡胶的冲击反映相对慢,幅度也相对小,反之,则较为强烈。     

论土地价格的本质及其来源

研究目的：论证土地价格的本质及来源,凝练土地经济学规律。研究方法：归纳与演绎法,文献研究法。研究结果：土地作为自然资源和生产要素,在人类社会出现土地私人占有以后就出现了土地价格;土地价格是在交换过程中形成的,是土地占有或放弃占有的对价;土地价格是土地利用能力的标尺,是土地财产价值量的经济表征;土地的本质属性决定了土地价格变化的特殊性;土地价格最终取决于土地利用能力,土地价格是其预期收益的购买价格。研究结论：土地价格最终来源于土地产出品价格,应遵循这一基本规律认识和解决土地经济问题。     

Are Shocks Transitory or Permanent? An Inquiry into Agricultural Commodity Prices

This paper contributes to the contentious topic of whether shocks to agricultural commodity prices are permanent or transitory. This is an important issue with regards to forecasting, economic modelling of agricultural prices and risk management. Past studies have not accounted for important characteristics of agricultural prices that matter when testing whether shocks to prices are permanent or transitory. These include the presence or absence of a deterministic trend, the possible break in the trend, non‐stationary volatility, and the problem of the initial deviation of commodity prices from their long‐run mean or trend. We conduct a comprehensive test that incorporates all these characteristics known to plague agricultural commodity prices. Though the conclusion is mixed, the balance is in favour of agricultural price shocks being permanent in nature. This result departs from the general view that in theory, agricultural prices should be stationary, suggesting that the controversy of whether shocks to agricultural prices are temporary or permanent is not yet over.     

World Commodity Prices and Domestic Retail Food Price Inflation: Some Insights from the UK

We focus on two aspects of the links between world commodity prices and retail food price inflation: first, the effects of exchange rates and other input costs, and second; the effects of the duration of shocks on world commodity markets, not just the magnitude of price spikes (the latter often commanding most attention). The UK offers a natural and rather unexplored setting for the analysis. Applying time series methods to a sample of 259 monthly observations over the 1990(9)–2012(3) period we find substantial and significant long‐term partial elasticities for domestic food price inflation with respect to world food commodity prices, the exchange rate and oil prices (the latter indirectly via a relationship with world food commodity prices). Domestic demand pressures and food chain costs are found to be less substantial and significant over our data period. Interactions between the main driving variables in the system tend to moderate rather than exacerbate these partial effects. Furthermore, the persistence of shocks to these variables markedly affects their effects on domestic food prices.     

Importing High Food Prices by Exporting: Rice Prices in Lao PDR

Lao PDR has extensive export controls on its staple food, glutinous rice, which keep domestic prices low relative to international prices. Using price, harvest, and export data this paper analyses how glutinous rice prices in Laos PDR are related to those in its trading partners, Thailand and Vietnam. We find that rice prices in Lao PDR are more likely to rise following a good harvest year than a bad or a normal year. This is consistent with export controls being relaxed after good harvests, leading to an increase in exports early in the season and rising prices later as stocks are depleted. There is thus a case for removal of trade restrictions since they give rise to price spikes while keeping the long‐term price of glutinous rice low, and thereby hinder increases in income from agriculture. However, since high rice prices are likely to affect the poor negatively in the short to medium term, a combination of an export tax and cash transfers is recommended during the transition period. Although this is a case study of Lao PDR, the findings may equally apply to other developing countries that export their staple food.     

Are commodity prices chaotic?

We conduct tests for the presence of low‐dimensional chaotic structure in the futures prices of four important agricultural commodities. Though there is strong evidence of non‐linear dependence, the evidence suggests that there is no long‐lasting chaotic structure. The dimension estimates for the commodity futures series are generally much higher than would be for low dimension chaotic series. Our test results indicate that autoregressive conditional heteroskedasticity (ARCH)‐type processes, with controls for seasonality and contract‐maturity effects, explain much of the non‐linearity in the data. We make a case that employing seasonally adjusted price series is important in obtaining robust results via some of the existing tests for chaotic structure. Finally, maximum likelihood methodologies, that are robust to the non‐linear dynamics, lend strong support to the Samuelson hypothesis of maturity effects in futures price changes.     

基于Panel Data模型的土地供应量对房价的影响研究

研究目的：定量反映土地供应量对房价的影响及其作用机制。研究方法：计量经济学方法。研究结果：一年前的土地供应量对房屋供应量的影响是正的,对房价的影响是负的,两者在统计上都是显著的,但土地供应量增加对降低房价的影响力非常小。两年前的土地供应量虽然影响房屋供应量,但却不影响房价。研究结论：影响中国当前房价的因素非常复杂,增减土地供应量对调控房价有一定作用,但必须同时有其他工具的辅助,否则其效果很可能不够显著。     

The Effect of Wal-Mart Supercenters on Grocery Prices in New England

The competitive price effect of Wal-Mart Supercenters on national brand and private label grocery prices in New England is examined. We use primary price data collected on several identical products from six Supercenters in Massachusetts, Connecticut, and Rhode Island and from conventional supermarkets. Taking into account demographics, store characteristics, and market conditions, we show that Wal-Mart decreases prices by 6 to 7% for national brand goods and by 3 to 8% for private label goods. Price decreases are most significant in the dry grocery and dairy departments. Moreover, Wal-Mart sets grocery prices significantly lower than its competitors.     

Derived Demand and Relationships between Prices at Different Levels in the Value Chain: A Note

In this paper we note that when there is only one variable factor in the intermediaries' production technology, prices at different levels in the value chain will move proportionally to each other over time. This is also the only general condition under which the elasticity of price transmission is equal to one, so that retail price signals are perfectly transmitted to primary product producers and vice versa. This allows a test of whether derived demand elasticities contain information about consumer elasticities using only prices. An empirical illustration is provided using data from the Norwegian cod sector.     

Prices paid for farmland in Ontario: Does buyer type matter?

In the wake of the substantial increases in farmland values that have occurred in Ontario since 2008, concerns have been expressed regarding the potential influence of nonfarmer buyers, such as investment companies and foreign buyers, on prices paid for farmland. To examine whether these concerns may be warranted, this paper estimates the impact of nonfarmer buyers on sale prices for farmland in Ontario, using a hedonic approach and farmland sales data from 2002 to 2016. Analysis is also conducted to determine whether marginal implicit prices of specific farm attributes differ between farmer buyers and nonfarmer buyers. The results indicate that nonfarmer buyers have paid higher prices for farmland, but only in near‐urban areas. In addition, differences in marginal implicit prices for farmland attributes are found, where farmer buyers value more highly attributes related to the agricultural productivity of the property while nonfarmer buyers value more highly attributes related to nonagricultural use. These results imply that the higher prices paid by nonfarmers may be attributable to the bid‐rent theory, as nonfarmers may be bidding more than farmers for farmland in near‐urban areas due to higher expected returns from future urban use of the land.     

Using Formula Prices in the Absence of Publicly Reported Prices: An Application for Segregated Early Weaned Pigs

A formula for deriving the price of segregated early weaned pigs using corn, soybean meal, and market hog prices was estimated by equating return on investment for the different phases of production. USDA reported prices were compared with prices derived from this and several other common formulas. Based on several accuracy measures, the estimated formula was better at predicting spot-market prices than other formulas. Producers appear to form price expectations based on futures plus expected basis rather than simply futures or current cash prices. However, the method of choosing price expectations will depend on the risk attitudes of the buyer and seller and their business relationship. Developing pricing formulas based on the framework outlined here (equal returns on investment) has merit for establishing prices in the absence of publicly reported information. However, it is important that users of the formula understand the conceptual framework of how and why it was developed.     

Food Aid, Food Prices, and Producer Disincentives in Ethiopia

Although the short-term aims of food aid are well conceived, strong concerns have been voiced regarding the long-term impacts of such aid on incentives for agricultural producers in recipient countries. This article examines the statistical link between food aid shipments and food prices in Ethiopia over the period 1996–2006. Monthly data from three markets and three commodities are used to estimate a system of seemingly unrelated regression models for food prices. Results indicate that previous year food aid shipments reduce prices in all producer and consumer markets. These effects, however, appear to be limited to the set of internationally traded commodities that are domestically marketed. A recursive regression procedure is used to identify the food aid threshold at which a negative aid effect emerges. Food aid shipments that constitute less than 10% of domestic production appear to be benign, but shipments above this level show signs of being disruptive to local markets. We use a simple policy simulation to argue that production-sensitive targeting, e.g., conditioning food aid on local food production, would help to circumvent disincentive effects.     

Supermarket Promotions and Food Prices: A Note

Using a sample comprising nearly 250,000 weekly prices from the largest seven UK supermarket chains, this note investigates two pricing practices that have attracted public interest: the tendency for promotions to ‘disguise’ rises in non‐sale prices and the inflation of prices prior to sales which ‘exaggerate’ the discount. Analysing price dynamics before and after periods of promotional discounting results show post‐sale prices are typically lower than pre‐sale prices, contrary to the disguise hypothesis. We do, however, find evidence of exaggeration of the discount, which may potentially explain why prices fall after discounts, although the evidence is not sufficiently widespread for this to be the sole cause. Results parallel the competition authority's view of supermarket promotions and point to the useful contribution that retail price microdata might play in keeping prices in check in countries where highly concentrated retail sectors raise similar concerns.     

永佃制下的田皮价格

本文从安徽歙县遗留的民间置产簿本及田皮买卖文契辑录田价及田皮价。比较之下可以看出田皮价格之波动远为剧烈；在多数年代田皮价超过田价。利用不同的田皮比价来计算吉尼系数，明显看出上涨的田皮价格可以进一步使地权分配平均化。