There are several aspects of carcass composition and quality which, as an integrated whole, determine carcass value. However, it is convenient, and informative, to restrict the study to quantitative (gravimetric) data and to remove the effect of carcass weight. If this is done, and if requirements to meet standard joints or cuts are imposed, there are only two factors which affect value: (a) the proportion of saleable meat in the carcass and (b) its distribution amongst joints of different value. There is an overriding importance of (a) in this context and the commercial significance of carcass classification schemes is dependent on the accuracy with which the proportion of saleable meat in carcasses can be predicted.