Quality and Quantity Several references have been made to quality. This is a concept much neglected also in 'mainstream' economics. But at least the textbook theory of value does have the merit of emphasising the role of demand. The marginal utility school does this to excess, in the sense that it understates the importance of conditions of production. But willingness to pay, valuation by the user, valuation in money, are seen as vital. A better machine, shoe, steak, will usually command a higher price. But the Marxist tradition is one of quantitative planning. Soviet experience shows how the centre cannot cope either with a fully disaggregated product mix, or with quality. The point is that, apart from the sheer impossibility of the centre handling detailed specifications, quality is by no means easy to define. It is sometimes specific: calorific content of coal, tensile strength, and so on; but frequently it is a matter of user convenience, or taste, of attractiveness - in fact value in use, valued by the user.