In addition to an enumeration of the kinds and values of goods produced, there is needed, for a proper understanding of the significance of these data resulting from a census, a record of the numbers of persons employed in the production of those goods and of the mechanical aids to production at their disposal. Infor mation as to the distribution of the value of the recorded pro duction between wages, returns to capital, taxation, profits, etc., will also have much importance, in view of the reaction of distri bution on productive efficiency ; but inquiries regarding the dis tributive allocation of the values produced do not appear to be an essential part of the census of production itself.
Information on these matters, like information regarding the quantities and values of imports and exports of the various classes of goods with which the census is concerned, is of very great importance in the application of the results secured by means of the census. The comparison of the imports and exports of any class of products with the amounts and values of similar products made within any country affords information of funda mental importance. For the aggregate of all industries it fur
nishes measures of the dependence of the material welfare of the country on its foreign trade. Further, since the material income of a country consists in the goods produced and in those which are obtained from abroad in exchange, a census of production furnishes a basis for measuring the amount of, and the changes in, the total income of the community. In so far, too, as capital goods and consumption goods are capable of distinction, the total of products applied to capital purposes, replacement and in crease together, can be ascertained. The formation of a reason able estimate of what is required for maintenance of the existing stock of capital enables an estimate to be made, of a correspond ing degree of reliability, of the increase of capital. Thus results of uncertain estimates formed on other principles can be sub mitted to useful tests.