Econometricians, as well as other scientists, are engaged in learning from their
experience and data - a fundamental objective of science. Knowledge so obtained
may be desired for its own sake, for example to satisfy our curiosity about aspects
of economic behavior and/or for use in solving practical problems, for example
to improve economic policymaking. In the process of learning from experience
and data, description and generalization both play important roles. Description
helps us to understand “what is” and what is to be explained by new or old
economic generalizations or theories....