There are a number of significant challenges researchers encounter when studying development over an extended period of time, including subject attrition, the changing of measurement structures across groups and developmental periods, and the need to invest substantial time and money. Integrative data analysis is an emerging set of methodologies…

Bayley's major contributions to developmental psychology are reviewed. These include her concern with measurement and methodology and her early anticipation of such topics as behavior genetics. Her work in such areas as androgyny and body build, motor and mental development, and maternal and child behaviors is summarized. (LB)