The major advances in American life expectancy achieved during the twentiet
h century began with the remarkable decline in infant mortality between 191
0 and 1930. Until the 1990s, explanations of this demographic event centere
d on improvements in nutrition, public health, and medical science. Recent
causal reappraisals emphasize the importance of changes in household-level
health behaviors in reducing infant deaths, changes that are consistent wit
h the maternal education campaigns engineered by Progressive Era reformers
at the U.S. Children's Bureau. Through qualitative and quantitative analyse
s of bureau reports and Public Use Micro Sample census data, we link the re
formers' philosophy and science to new evidence and conclusions about early
improvements in infant survival.