Regression specifications in applied econometrics frequently employ regressors, which are defined as the product of two other regressors to form an interaction. Unfortunately, the interpretation of the results of these models is not as straight forward as in the linear case. In this article, we...

The traditional textbook approach to avoiding the dummy trap problem is to delete a category from each qualitative variable. This paper illustrates an alternative constraint which can be used to transform conventional dummy variable coefficients. This constraint serves to simplify their...

One form of data reduction is cluster analysis which is used to separate detailed data into constituent groups. This paper illustrates a useful application of cluster analysis to the data reduction of detailed discrete responses of a type that are often found in large surveys. This method is...

The presence of threshold effects or convex damage functions implies that the composition of pollutants may be as important in the determination of health outcomes as the level of pollution. As such, greater specialization in particular environmental hazards may suggest increasing costs from...

The concept of an environmental Gini coefficient has been used recently by several researchers. In line with Paglin's historical critique of the income Gini coefficient, an environmental Paglin-Gini is proposed and estimated, more carefully considering the notion of 'perfect environmental...