Extending the Concepts of Demand and Supply in Economic Education

Abstract

specify the structural equations of the model (e.g., by adding or deleting variables from the demand equation) [2]. Indeed, it is not uncommon in some types of empirical demand functions for the price variable to be excluded altogether [3]. Therefore, I would contend that in discussions relevant to theoretical demand functions encountered in undergraduate textbooks, it is no less arbitrary, nor creates no less of a mistaken impression, to include variables which do not follow directly from the assumptions, as it would be to ignore those variables which do. In expositions relevant to empirical demand functions, on the other hand, there is no substitute for determining whether or not a function is properly specified and whether or not the variables are statistically significant. It would be in error to assume the significance of any variable a priori. On these grounds, therefore, I would suggest that our textbook authors proceed to replace the conventional (theoretical) treatment of demand with a multivariable relationship, but with caution. For most of my students, I think the differences between theoretical functions and empirical functions worthy of preservation. And for my best students, I should wish them to become good theoreticians as well as good econometricians.