Structural Change and Long‐run Relationships between US and EU Wheat Export Prices

This paper analyses the nature of the long‐run relationship between US and EU wheat export prices over the period 1981–2000. We employ a novel approach of testing for cointegration with structural change developed by Barassi and Taylor (A Test for Change in the Cointegrating Rank, University of Birmingham, Birmingham, 2004). The method enables us to determine the breakpoint, which is found to occur after the 1992 CAP reforms were implemented. On analysing the two separate subperiods, we find no evidence of a long‐run relationship prior to the 1992 CAP reform. However, clear evidence of a long‐run relationship is found after the CAP reforms were implemented. Further analysis reveals that, in the post‐CAP reform period, the EU wheat prices follow then US soft wheat prices, consistent with the EU export subsidy regime over this period, albeit that export subsidies by the EU have been relatively small.     

Agricultural Commodity Price Shocks and Their Effect on Growth in Sub‐Saharan Africa

Commodity price shocks are an important type of external shock and are often cited as a problem for economic growth in Sub‐Saharan Africa. We choose nine Sub‐Saharan African countries that are heavily dependent on a single agricultural commodity for a significant portion of their income. This paper quantifies the impact of agricultural commodity price shocks using a structural non‐linear dynamic model. The novel aspect of this study is that we determine whether the response of per capita GDP for the selected Sub‐Saharan African countries is different to unexpected increases in agricultural commodity prices as opposed to decreases in prices. We conclude that there is very little evidence that an unanticipated price increase (decrease) will lead to a significantly different response in per capita incomes.     

A hybrid commodity price‐forecasting model applied to the sugar–alcohol sector

Accurate price forecasting for agricultural commodities can have significant decision‐making implications for suppliers, especially those of biofuels, where the agriculture and energy sectors intersect. Environmental pressures and high oil prices affect demand for biofuels and have reignited the discussion about effects on food prices. Suppliers in the sugar–alcohol sector need to decide the ideal proportion of ethanol and sugar to optimise their financial strategy. Prices can be affected by exogenous factors, such as exchange rates and interest rates, as well as non‐observable variables like the convenience yield, which is related to supply shortages. The literature generally uses two approaches: artificial neural networks (ANNs), which are recognised as being in the forefront of exogenous‐variable analysis, and stochastic models such as the Kalman filter, which is able to account for non‐observable variables. This article proposes a hybrid model for forecasting the prices of agricultural commodities that is built upon both approaches and is applied to forecast the price of sugar. The Kalman filter considers the structure of the stochastic process that describes the evolution of prices. Neural networks allow variables that can impact asset prices in an indirect, nonlinear way, what cannot be incorporated easily into traditional econometric models.     

Inter‐ and intra‐seasonal crop acreage response to international food prices and implications of volatility

Understanding how producers make decisions to allot acreage among crops and how decisions about land use are affected by changes in prices and their volatility is fundamental for predicting the supply of staple crops and, hence, assessing the global food supply situation. This study makes estimations of monthly (i.e., seasonal) versus annual global acreage response models for the world's principal staple food crops: wheat, corn, soybeans, and rice. Primary emphasis is given to the magnitude and speed of the allocation process. Estimation of intra‐annual acreage elasticity is crucial for expected food supply and for input demand, especially in the light of the recent short‐term volatility in food prices. The econometric results indicate that global crop acreage responds to crop prices and price risks, input costs as well as a time trend. Depending on respective crop, short‐run elasticities are about 0.05 to 0.40; price volatility tends to reduce acreage for some of the crops; comparison of the annual and the monthly acreage response elasticities suggests that acreage adjusts seasonally around the globe to new information and expectations. Given the seasonality of agriculture, time is of an essence for acreage response. The analysis indicates that acreage allocation is more sensitive to prices in the northern hemisphere spring than in winter and the response varies across months.     

Volatility in Cereal Prices: Intra‐ Versus Inter‐annual Volatility

Intra‐annual (within crop year) price volatility and inter‐annual (between crop years) price volatility are measured for wheat, maize, rice, barley, oats and rye. A set of explanatory variables is used in a pooled regression to explain variations in these price volatilities. With low cereal stocks, supply (yield) shocks (defined here as volatilities, as for the price volatilities) mostly influence inter‐annual volatility while other influential factors are the crude oil price and exchange rate. Cereal demand and interest rate shocks combined with low stocks affect intra‐annual volatility, while other explanatory factors include exchange rate and crude oil price shocks. The derivatives market activity appears to have no significant effect on either intra‐ or inter‐annual volatility. In contrast, large cereal stocks and a well‐functioning international cereal market reduce the effects of shocks in the explanatory variables on both intra‐ and inter‐annual volatilities.     

Black Sea and World Wheat Market Price Integration Analysis

In 2008–10, Russia and Ukraine together exported an average of 29 million tons of wheat per year, and have become important players in the international wheat market. This research summarizes the short‐ and long‐run wheat price dynamics between Ukraine and Russia, and other major wheat exporters—the United States, European Union (EU), and Canada—from 2004 to 2010. Tests of market price co‐integration (Johansen maximum likelihood test and residual‐based tests) as well as threshold error correction techniques were performed for this purpose. The results suggest that Russian wheat prices were co‐integrated with EU and U.S. wheat prices but not with Canadian wheat prices. Ukrainian wheat prices were found to be co‐integrated with French wheat prices only. The estimated long‐run wheat price transmission elasticities were estimated to be equal to 1.04 between Russian and French (a representative country of the EU) wheat prices, 1.16 between Russian and U.S. wheat prices, and 1.05 between Ukrainian and French wheat prices. We also found the short‐term relationships between the co‐integrated series to be statistically significant. Price adjustments in all co‐integrated prices were found to be symmetric.     

U.S. corn exports: the role of the exchange rate

Time series econometric methods are applied to monthly observational data over the period 1978-1942 on real exchange rates, real corn prices, corn export sales, and corn export shipments for the United States. In-sample fit and out-of-sample forecast results are used to discern whether exchange rates have elicited systematic responses in U.S. corn prices, sales and shipments, and whether the dynamic transmission mechanisms tying these variables together have changed over time. A structural break appears to have occurred in early 1985. No cointegration is found between exchange rates, price, sales, and shipments in either sub-period. Influences are all short-run or between stationary variables. The role of the exchange rate appears to have moderated in the post-1985 period. Implications for policy analysis are discussed.     

Welfare effects of maize technologies in marginal and high potential regions of Kenya

This paper describes the findings of a study that used a multi‐market model to assess the potential impact of improved maize technologies on the welfare of various types of rural and urban households in Kenya. The modelling results indicate that technologies developed for high potential regions are likely to have more profound aggregate impacts on maize production and lead to greater reductions in import demand (if prices are controlled) or maize prices (if maize prices are flexible). Technology adoption in high potential regions is likely to have substantially greater positive impacts on aggregate real incomes, but inferior income distributional outcomes compared to technology adoption in marginal regions.     

Buyer Collusion and Efficiency of Government Intervention in Wheat Markets in Northern India: An Asymmetric Structural Auctions Analysis

This article uses auction theory to analyze wholesale markets for wheat in Northern India. This approach enables us to characterize the market in terms of buyer asymmetries, to detect the existence of collusion, and to quantify its impact on market prices. We show that buyer asymmetries exacerbate the downward impact of collusion on prices. The article also considers whether the government paid too much for the wheat it procured at the minimum support price, and shows that for our sample it did not. The article is based on a primary survey of two wholesale markets in North India.     

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.     

Using a functional approach to test trending volatility in the price of Mexican and international agricultural products

In this article, we extend the traditional GARCH(1,1) model by including a functional trend term in the conditional volatility of a time series. We derive the main properties of the model and apply it to all agricultural commodities in the Mexican CPI basket, as well as to the international prices of maize, wheat, swine, poultry, and beef products for three different time periods that implied changes in price regulations and behavior: before the North American Free Trade Agreement (NAFTA; 1987–1993), post‐NAFTA (1994–2005), and commodity supercycle (2006–2014). The proposed model seems to adequately fit the volatility process and, according to heteroscedasticity tests, also outperforms the ARCH(1) and GARCH(1,1) models, some of the most popular approaches used in the literature to analyze price volatility. Our results show that, consistent with anecdotal evidence, price volatility trends increased from the period 1987–1993 to 1994–2005. From 1994–2005 to 2006–2014, trends decreased but the persistence of volatility increased for most products, especially for international commodities. In addition, we identify some agricultural products such as avocado, beans, and chicken that, due to their increasing price volatility trends in the 2006–2014 period, may present a risk for food inflation in the short run.     

A roller coaster ride: an empirical investigation of the main drivers of the international wheat price

Over the last decade, commodity prices have registered substantial booms and busts marked by extreme volatility. Wheat in particular, one of the main nonoil commodities, has registered a roller coaster in price levels which seems to be inconsistent with supply and demand fundamentals. To acutely investigate the drivers of wheat prices and quantify their impact, a vector error correction model (VECM) has been used. The exogenous variables have been distinguished into four groups: market‐specific factors, broad macroeconomic determinants, speculative components, and weather variables. The quadriangulation of the determinants will enable us to better understand the movements in wheat price and identify the specific role of each component. The results show that a mix of factors are contributing to wheat price movements, including speculation, global demand, and real effective exchange rate.     

The transmission of world maize price to South African maize market: a threshold cointegration approach

This article seeks to provide an explanation for the relationship between domestic maize price in South Africa and world maize prices in order to evaluate comovement and transmission of world prices to domestic prices in sub‐Sahara African countries. This is done by comparing nested and nonnested models that capture different forms of nonlinearity in the price spread. Adopting a Bayesian approach that allows for comparison of models using Bayes factor, we found that the relationship between South African price and world price for maize indicates the presence of nonlinearity in price transmission with three regimes that is triggered by the price spread in previous period.     

The impact of deal‐proneness on WTP estimates in incentive‐aligned value elicitation methods

Even after controlling for hypothetical biases, some incentive‐aligned value elicitation methods still produce different willingness‐to‐pay (WTP) estimates. In this study, we compare WTP estimates from three incentive‐aligned value elicitation methods: real choice experiment (RCE), real double‐bounded dichotomous contingent valuation (RCVM), and Becker–DeGroot–Marschak auction (BDM). We find that participants’ aggressiveness in obtaining low prices (i.e., “deal‐proneness”) influences WTP estimates in the BDM auction, but not those elicited from the RCE and RCVM. The participants with higher levels of deal‐proneness tend to submit lower bids in the BDM auction. The discrepancies in WTP estimates between different incentive‐aligned procedures are narrower for participants with lower levels of deal‐proneness. Our results indicate that the bids in BDM auctions may be understated and the auction mechanism may induce the “gambling behavior” of people who are deal‐prone. That is, whether the BDM auction is truly incentive‐aligned is again called into question. We also discuss the practical implications for food retailers.     

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.     

Design Factors Influencing Willingness‐to‐Pay Estimates in the Becker‐DeGroot‐Marschak (BDM) Mechanism and the Non‐hypothetical Choice Experiment: A Case of Biofortified Maize in Zambia

Two of the experimental methods used to estimate willingness‐to‐pay (WTP) for a non‐market good, the Becker‐DeGroot‐Marschak (BDM) mechanism and the non‐hypothetical choice experiment (nHCE) often lead to significantly different WTP estimates, complicating the choice between the methods. In Zambia the same group of researchers used both techniques to evaluate WTP for orange maize, which provides more vitamin A than other varieties. This provided an opportunity to analyse the sources of the difference. In the BDM experiment, one group of respondents was provided with more training opportunities than the other, and made higher bids. Accounting for lexicographic behaviour in the nHCE reduced the estimated WTP. These two design factors together resulted in a decrease in the WTP difference for orange maize (1,279–632 ZMK) although the difference remains statistically significant. More training was also shown to eliminate the effects of different orders in which maize varieties were presented.     

Dynamics of rice prices and agricultural wages in the Philippines

Rice trade liberalization in the Philippines should decrease domestic rice prices impacting both agricultural wages and the welfare of agricultural wage earners. This study examines the short-run and long-run relationship between rice prices and agricultural wages in the Philippines using a neoclassical wage determination model. Three empirical frameworks are used—a cointegration/error correction framework, which assumes nonstationary variables in long-run equilibrium, a first difference model that assumes nonstationary variables but no long-run equilibrium, and an OLS framework that assumes the model variables are stationary. Conclusions are reasonably robust across the three empirical frameworks with wages adjusting positively to rice price changes with a short-run elasticity of 0.29 to 0.57, and a long-run elasticity of 0.70 to 1.0 in preferred models. An analysis of welfare implications suggests that although households that are heavily reliant on agricultural wages for income will be adversely affected by rice price decreases, other households will benefit.     

Price shock transmission: evidence from the wheat‐bread market value chain in Ethiopia

This study assesses the degree of vertical price transmission along the wheat‐bread value chain in Ethiopia. This is pursued by applying a vector error correction model and an impulse response analysis using monthly price data for the period 2000–2015. Our analysis considers transmission of price shocks across different market levels, including from the international and domestic wheat grain markets at the upstream to the domestic wheat bread market at the downstream of the value chain. The empirical findings indicate that significant cointegration exists across prices of the different market stages. There is a transmission from international prices to domestic prices at downstream markets, in particular to flour and bread prices. Prices at upstream markets are largely influenced by the domestic wholesale market. In general, the speed of adjustment is quite slow with a half‐life of about one year for restoring the equilibrium price relationship. As price margins between the different market stages in the value chain have substantially decreased in the last 15 years, higher transmission, and thus exposure to international market shocks, can be expected in the future. The results also show that causal relationships exist between prices at different market stages—with the wholesale market identified as the key market level where prices and price expectations are formed.     

Asset‐based poverty transition and persistence in rural China

This article tests empirically for transition and persistence of poverty in rural China based on the theory of asset‐based poverty traps. It proposes an analytical framework mitigating the problem of endogenous switching between accumulation regimes and disentangling the true state‐dependence of poverty. Specifically, a dynamic asset threshold separating households into downward and upward mobility regimes is identified after taking households’ unobserved characteristics and observed regime‐differentiated accumulation strategies into account. The static analysis identifies causality running from settling into a downward mobility regime to the probability of poverty measured by consumption. Furthermore, allowing for endogenous initial poverty status, the dynamic analysis finds strong true state‐dependence in poverty. Households with the same characteristics are nearly twice as likely to be poor as if they had not previously switched to the accumulation regime. Assets below the dynamic threshold serve as a conduit through which poverty propagates itself. Factors that help to break this vicious circle are identified.     

Estimating shadow price for symbiotic nitrogen and technical efficiency for legume‐based conservation agriculture in Malawi

Determining the value of legumes as soil fertility amendments can be challenging, yet this information is required to guide public policy and to incentivise prescribed land‐management practices such as conservation agriculture. We use a directional input distance function (DIDF) to estimate shadow prices for symbiotic nitrogen and the technical efficiency for mixed maize‐legume production systems in Malawi. The shadow prices reflect the trade‐off between fertiliser nitrogen and symbiotic nitrogen required to achieve a given quantity of output. Our results reveal considerable technical inefficiency in the production system. The estimated shadow prices vary across farms and are, on average, higher than the reference price for commercial nitrogen. The results suggest that it would be beneficial to redesign the current price‐support programs that subsidise chemical fertilisers and indirectly crowd‐out organic soil amendments such as legumes.