This case study focuses on a longitudinal study of changes in public acceptance of evolution in the United States. Change over time is often a central issue in social science research questions. There are two kinds of change over time. Time-series studies address change in populations or groups over time. Longitudinal studies address changes in individuals over time (see related time-series case study in this volume). This case study will describe the process for conceptualizing a longitudinal study and the challenges of obtaining funding for multi-year longitudinal studies. This case study is based on a 33-year longitudinal study--the Longitudinal Study of American Life (LSAL)--which began with a national probability sample of 7th and 10th grade students in public schools in the United States. The same individuals have been surveyed and studied for 33 years--from middle school to middle age. Readers will be challenged to think about the maintenance of a multi-decade longitudinal study and the needed adjustments to changing data collection modes over the three decades of the study. [This content is provided in the format of an e-book.]