We study the class of multivariate distributions in which all bivariate regressions can be linearized by separate transformation of each of the variables. This class seems more realistic than the multivariate normal or the elliptical distributions, and at the same time its study allows us to combine the results from multivariate analysis with optimal scaling and classical multivariate analysis. In particular a two-stage procedure which first scales the variables optimally, and then fits a simultaneous equations model, is studied in detail and is shown to have some desirable properties.

An interdependent multivariate linear relations model based on manifest, measured variables as well as unmeasured and unmeasurable latent variables is developed. The latent variables include primary or residual common factors of any order as well as unique factors. The model has a simpler parametric structure than previous models, but it is designed to accommodate a wider range of applications via its structural equations, mean structure, covariance structure, and constraints on parameters. The parameters of the model may be estimated by gradient and quasi-Newton methods, or a Gauss-Newton algorithm that obtains least-squares, generalized least-squares, or maximum likelihood estimates. Large sample standard errors and goodness of fit tests are provided. The approach is illustrated by a test theory model and a longitudinal study of intelligence.

The primary objective of this study was to assess the impact of catfish imports and tariffs on the U.S. catfish industry, with particular focus on the U.S. International Trade Commission ruling on Vietnam in 2003. Given the importance of Vietnam to the U.S. catfish market, it was assumed that catfish import prices would increase by 35 percent if the maximum tariff was imposed on catfish from Vietnam. With the tariff, domestic catfish prices at the wholesale level would increase by $0.06 per lb, and farm prices by $0.03 per lb. Processor sales would increase by 1.66 percent. Total welfare at the wholesale level would increase from $69.2 million to $71.7 million, an increase of about 3.63 percent, and processor and farm revenue would increase by 4.4 percent and 5.8 percent, respectively. These results represent the greatest possible benefit and suggest modest gains for the U.S. catfish industry.

Merchandisers of landscape plants can increase the effectiveness of their marketing strategies by identifying target markets. Using a full information maximum likelihood tobit procedure on a system of three equations, target markets for different types of retail outlets in Georgia were identified. The results lend support and empirical evidence to the premise that different retail outlet types have different target markets and thus should develop different market strategies. The estimated target markets are identified and possible marketing strategies suitable for each type of retail outlet are suggested.

The impacts of using export taxes as a price control in a multi-market framework are explored using the cotton and yarn sectors in Pakistan as examples. Results show that the export tax on cotton increased domestic consumption and decreased exports of cotton in Pakistan, transferring income from cotton producers to yarn spinners and the government. There was a social loss to Pakistan in the cotton sector. The export tax on cotton increased domestic yarn production, consumption, exports, and incomes of yarn spinners, but resulted in a large transfer (social loss) out of the yarn sector.