This paper introduces a flowchart-based methodology for describing the movement of foster youth in and out of placements of differing types and durations. This longitudinal methodology is designed to be sufficiently simple to appeal to policymakers and administrators seeking to chart the movement of groups of youth over time and the sequencing of their placements, and sufficiently descriptive to be of use to researchers seeking to predict the placement trajectories of subgroups of foster youth. The paper provides an example of the use of the method drawing upon state administrative data from a large study of preadolescent and adolescent youth in foster care situated in Oregon. Implications for the application of the methodology to different issues of interest to researchers, policymakers, and administrators are discussed.