Developmental science rests on describing, explaining, and optimizing intraindividual changes and, hence, empirically requires longitudinal research. Problems of missing data arise in most longitudinal studies, thus creating challenges for interpreting the substance and structure of intraindividual change. Using a sample of reports of longitudinal…

The study of adolescent development rests on methodologically appropriate collection and interpretation of longitudinal data. While all longitudinal studies of adolescent development involve missing data, the methods to treat missingness that have been recommended most often focus on missing data from cross-sectional studies. The problems of…

The National Longitudinal Transition Study of Special Education Students (NLTS) provides information to practitioners, policymakers, researchers, and others in the special education community regarding the transition of youth with disabilities from secondary school to early adulthood. The sample for the study, which began in 1987, involves more…

There is a need for educational research even during financial difficulties. Wisdom and efficiency in spending, careful data collection, and collaboration among agencies should be important goals while resources are scarce. Considering the situation, this paper describes critical issues in elementary and secondary education and the manner in which…