We compare the ability of three preference elicitation methods (hypothetical choices, nonhypothetical choices, and nonhypothetical rankings) and three discrete-choice econometric models (the multinomial logit [MNL], the independent availability logit [IAL], and the random parameter logit [RPL]) to predict actual retail shopping behavior in three different product categories (ground beef, wheat flour, and dishwashing liquid). Overall, we find a high level of external validity. Our specific results suggest that the nonhypothetical elicitation approaches, especially the nonhypothetical ranking method, outperformed the hypothetical choice experiment in predicting retail sales. We also find that the RPL can have superior predictive performance, but that the MNL predicts equally well in some circumstances. experiment.

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How Closely Do Hypothetical Surveys and Laboratory Experiments Predict Field Behavior

In this article, we consider the impact of European Union (EU) export subsidy reductions on the U.S. dairy trade. We assume reductions of 36% similar to the 1995 World Trade Organization agreement. The price substitutability between U.S. and EU dairy products is estimated using a Rotterdam-type production model. Past analyses have suggested that EU export subsidy reductions will increase U.S. dairy exports because the removal of EU subsidies will raise EU export dairy prices, rendering U.S. dairy products more competitive on world markets. This is partially true for nonfat dry milk, where our projections indicate an increase of 4.6% in U.S. exports. U.S. cheese, butter, and whey exports, on the other hand, rise by only 0.2, 0.1, and 0.2%, respectively. The main reason for the relatively modest gains is that the U.S. and EU dairy products are independent, not substitutes, for one another in a majority of the countries studied. [JEL classifications: Q17, Q18, F53] © 2008 Wiley Periodicals, Inc.

The impact of EU export subsidy reductions on U.S. dairy exports

We compare the ability of three preference elicitation methods (hypothetical choices, non-hypothetical choices, and non-hypothetical rankings) and three discrete-choice econometric models (the multinomial logit, the independent availability logit, and the random parameter logit) to predict actual retail shopping behavior in three different product categories (ground beef, wheat flour, and dishwashing liquid). Overall, across all methods, we find a reasonably high level of external validity. Our results suggest that the non-hypothetical elicitation approaches, especially the non-hypothetical ranking, outperformed the hypothetical choice experiment in predicting retail sales. We also find that the random parameter logit can have superior predictive performance, but that the multinomial logit predicts equally well in some circumstances.

External Validity of Hypothetical Surveys and Laboratory Experiments

In this work, we analyse EU soybean and maize imports using a demand system borrowed from the differential approach to firm theory. Alongside providing own-price and cross-price (i. e. cross-country) elasticities for these two products, we test whether source-specific characteristics exert any influence on complementarity and substitution patterns between international exporters. Specifically, we look at country differences stemming from supply chain efficiency and the asynchronous approval of Genetically Modified (GM) varieties. We do so by introducing two measurements for such features into a linear demand model specified by Laitinen and Theil (1978). Estimation results suggest that the EU import structure is not affected by differences in supply chain efficiency between overseas suppliers while, depending on the product, asynchronous approval does seem to have an influence. We find that imports of maize are more sensitive than those of soybeans to differences in approval statuses between international exporters and the EU. Since soybean availability is a limiting factor for the EU feed industry, avoiding stock shortages may be a priority for European importers, hence the weaker effect of asynchronous approval. On the other hand, the substantial EU self-sufficiency for maize places more emphasis on product characteristics and prices.

The Determinants of the EU Import Demand for Soybean and Maize: What Role for GMOs?

Given the importance of EU demand for chilled fish fillets to the exporting sectors in Tanzania and Uganda, this study estimated the EUs import demand for fillets by country of origin to assess the competitiveness of exporters. Results imply that prices in Tanzania and Uganda had an insignificant impact on total imports expenditures in the EU. Conditional and unconditional cross-price effects indicated that exports from Lake Victoria did not compete with exports from other suppliers, such as Iceland, Norway and ROW. Import demand forecasts showed that market share in the EU should remain relatively unchanged given the trend in prices.

International Trade and Competitiveness of Lake Victoria Fillets in the EU

A previous study showed that imposing economic restrictions improves the forecasting ability of food demand systems, thus warranting their use even when they are rejected in-sample. This article evaluates whether this result is due to economic restrictions enhancing degrees of freedom or containing nonsample information. Results indicate that restrictions improve forecasting ability even when they are not derived from economic theory, but theoretical restrictions forecast best.

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Elizabeth A. Murphy

Papers

Do economic restrictions improve forecasts