GianCarlo Moschini

Units of Measurement and the Stone Index in Demand System Estimation

The Stone index typically used in estimating linear almost ideal demand systems is not invariant to changes in units of measurement, which may seriously affect the approximation properties of the model. A modification to the Stone index, or use of a regular price index instead, are both desirable practices in estimating linear AI models.

Intellectual Property Rights and the Welfare Effects of Agricultural R&D

We review intellectual property rights in agriculture and outline a modeling framework that accounts for relevant institutional features of agricultural R&D. The analysis emphasizes vertical market linkages whereby agricultural innovations adopted by farmers are produced upstream by input suppliers. It is argued that the conventional assumption of competitive pricing cannot hold when new technologies are produced by private firms because such innovations are typically protected by intellectual property rights (such as patents) that confer (limited) monopoly rights to discoverers. The implications of intellectual property rights for the welfare evaluation of agricultural R&D are derived, and it is shown that conventional methods usually overestimate the welfare gains from agricultural innovations. Copyright 1997, Oxford University Press.

Modeling the Pattern of Structural Change in U.S. Meat Demand

The hypothesis of structural change in U.S. meat demand is tested in a four-meat almost ideal demand system with parameters following a gradual switching regression model. The results support the notion that structural change partly explains the observed U.S. meat consumption patterns. Structural change is biased against beef, neutral for pork, in favor of chicken and fish, and it does not affect estimated elasticities. The estimated path of structural change implies a rapid transition to a new regime in the mid-1970s, although a smooth path cannot be ruled out.

Maintaining and Testing Separability in Demand Systems

We derive a general elasticity representation of the necessary and sufficient conditions for direct weak separability of the utility function. Parametric restrictions required to implement the separability conditions are presented for three common demand systems: the Almost Ideal, Translog, and Rotterdam. Our empirical application uses the Rotterdam model to test a few separable structures within a complete U.S. demand system emphasizing food commodities. Results, based on size-corrected likelihood ratio tests, provide support for commonly used separability assumptions about food and meat demand.

The Hedging Role of Options and Futures under Joint Price, Basis, and Production Risk

This paper analyzes the optimal production and hedging decisions for firms facing futures price, basis, and production risk, assuming futures and options can be used. Using constant absolute risk aversion utility and normal distributions, the authors derive an exact solution and show that joint production and price risk lead to a hedging role for options. Risk averse firms that can use each hedging instrument will generally have higher (expected) output. Using Iowa data for soybeans, the parameters of the joint distribution of future prices, cash prices, and yields are estimated and the results are used to approximate optimal hedging decisions for soybean producers. Copyright 1995 by Economics Department of the University of Pennsylvania and the Osaka University Institute of Social and Economic Research Association.

Futures Hedging Under Price, Basis, and Production Risk

We consider the hedging problem of a firm that has three sources of risk: price, basis, and yield uncertainty. An exact solution for the optimal futures hesge is derived under the assumption that the three random variables are joint normally distributed and that utility is of the CARA type. Unlike the mean-variance approximation applied in previous research, we show that the optimal hedge does depend on risk attitudes, even when the agent perceives the futures price as being unbiased. The theoretical results are applied empirically to the problem of hedging soybean production in Iowa. The exact solution, relying on CARA and normality, is compared with numerical solutions under lognormal distributions and CRRA utility.

Production, Hedging, and Speculative Decisions with Options and Futures Markets

This paper analyzes production, hedging, and speculative decisions when both futures and options can be used in an expected utility model of price and basis uncertainty. When futures and option prices are unbiased, optimal hedging requires only futures (options are redundant). Options are used together with futures as speculative tools when market prices are perceived as biased. Straddles are used to speculate on beliefs about price volatility and to hedge the futures position used to speculate on beliefs about the expected value of the futures price. Mean-variance analysis in general is not consistent with expected utility when options are allowed.

Geographical Indications and the Competitive Provision of Quality in Agricultural Markets

The economics of geographical indications (GIs) is assessed within a vertical product differentiation framework that is consistent with the competitive structure of the agricultural sector with free entry/exit. It is assumed that certification costs are needed for GIs to serve as (collective) credible quality certification devices, and production of high-quality product is endogenously determined. We find that GIs can support a competitive provision of quality that partly overcomes the market failure and leads to clear welfare gains, although they fall short of delivering the (constrained) first-best level of the high-quality good. The main beneficiaries of the welfare gains are consumers. Producers may also accrue some benefit if the production of high-quality products draws on scarce factors that they own.

Innovation and Trade with Endogenous Market Failure: The Case of Genetically Modified Products

A partial-equilibrium, two-country model is developed to analyze implications from the introduction of genetically modified (GM) products. In the model, innovators hold proprietary rights, farmers are (competitive) adopters, some consumers deem GM food to be inferior in quality to traditional food, and the mere introduction of GM crops affects the costs of non-GM food (because of costly identity preservation). Among the results derived, it is shown that, although GM innovations have the potential to improve efficiency, some groups can be made worse off. Indeed, it is even possible that the costs induced by GM innovations outweigh the efficiency gains.

The semiflexible almost ideal demand system

Abstract The concept of a semiflexible functional form is applied to the Almost Ideal (AI) demand system. This yields a demand model that is more parsimonious than standard ones while preserving a degree of flexibility, that satisfies the curvature property of concavity of the underlying expenditure function (at least locally), and that preserves the desirable properties of the AI model (aggregation across consumers and nonlinearity of the Engel curves). The model is illustrated with an application to a relatively large demand system emphasizing food consumption.