The practice of science as a mode of discovery is subject to change. This paper examines the "sciences" practiced by G. Stanley Hall in his "Adolescence" of 1904 and by contemporary researchers who study youth in 2004. After briefly reviewing the nature of Hall's empiricism, we draw on a representative sample of articles (n=182) published between 1999 and 2004 in specialty journals to analyze the interdisciplinary science of adolescence today. Results reveal that Hall was largely concerned with the conceptual and empirical description of phenomena, and he seldom offered causal explanations. In contrast, contemporary research frequently neglects description and emphasizes causal modeling. While a shift in focus from description to causation may seem a natural progression, we conclude by arguing that description is necessary even for a "mature" science. The study of adolescence needs a new regime of scientific practice that fully appreciates the value of both description and causal modeling.