BY JOSEPH WAKSBERG AND EDWIN D. GOLDFIELD

MORRIS HANSEN WAS THE most influential statistician in the evolution of survey methodology in the twentieth century. Early in his career at the Census Bureau he put together and directed a staff of mathematical statisticians and other survey methodologists whose aim was to systematically define the principal problems in the conduct of surveys, carry out research on these problems, and develop the statistical methods necessary to overcome them. This work included the development of sampling theory necessary for the efficient conduct of large-scale national surveys, the establishment of formal quality control methods for surveys, and the derivation of theory and models for analyses of nonsampling errors.

Hansen prodded the Census Bureau into accepting such innovations as the purchase of the first computer for statistical purposes, the development of optical scanning equipment, the introduction of self-enumeration and mail in both demographic and economic censuses, and other survey techniques now commonly used by both government and private organizations. He anticipated the concern that would arise over the completeness of coverage in decennial population censuses and, long before the current interest in the subject, he persuaded the bureau to adopt procedures de-