Professor Rudra’s book, meant more for postgraduate students than for the layman, is an excellent survey of one approach to planned development in India. It deals with the use of ‘formal’ models of economic relationships—‘formal’ in the sense that these relationships are encapsulated in mathematical equations involving exactly specified variables.
Such formalism has always had its critics both from within the profession and from outside. Two types of arguments are offered against this—one is that economic relationships are inexact and cannot be represented in the form of equations without unacceptable distortions and the second is that, even though the relationships are, in principle, exact, they are too complicated to be embodied in the simple mathematical forms typically used in economic models. Both types of arguments have a very simple point—that the use of formal models in planning leads to error.