Social and economic change since the Great Depression :

The 1940 census has been termed the first modern census. It was the first to ask about income and seek a wide range of other social and economic information, the first to be designed and planned by a full-time professional staff that included social scientists. Since then the decennial censuses have become increasingly detailed, taking advantage of advances in sampling techniques and, beginning in 1960, of computerization to pennit the release of public use sample tapes pmviding data on a host of household and personal characteristics.