The profusion of American statistics is a frequent source of astonishment to statisticians of other nations. Statistics are assembled and published by official agencies at all levels of government; by trade and industrial associations; by individual business concerns; by the church, universities, and the press; by professional research organizations; by a multitude of societies and associations with innumerable aims and programs; and sometimes by the plain citizen himself. Collectively, the statistical activities of the nation comprise a system in the same sense that the activities of four and one-half million business units comprise a national economic system.

There is, in fact, a functional relationship between the national statistical system and the socio-economic order of which it is a part. The primary functions of social and economic statistics are to illuminate practical problems, to assist in the determination of policies, and to aid in arriving at administrative decisions. No sharp line can be drawn in these respects between public and private affairs. Statistics find their raison d'etre as tools, to be used by public officials and by all manner of private interests, and in each case to make some part of the socio-economic system work more effectively.