Methodological Issues in the Design of Longitudinal Research: Principles and Recommendations for a Quantitative Study of Teachers’ Careers

In this paper, we initiate a discussion of the possible methodological features of a potential new national longitudinal study of teachers’ careers. We use a review of the substantive and methodological literatures and “pseudolongitudinal” analyses of data drawn from the National Center for Education Statistics’ Schools and Staffing Survey and Teacher Follow-Up Survey to support our arguments. Our presentation is framed by six key principles of research design that are then used to support concrete recommendations about whom should be studied, how often they should be observed, and for how long the study should continue. Our six design principles assert that, in the new study, we must collect truly longitudinal data, view time as both an outcome and a predictor, collect data on both time-varying and time-invariant measures, collect data prospectively whenever possible, collect data beginning in multiple base years, and collect data at all relevant levels of the organizational hierarchy. Although it is impossible to define a single research design that is optimal for answering all research questions about the teaching career, we recommend that the new study should sample from the population of teachers who are beginning their first, second, third, and subsequent spells, that each of these teachers be followed for at least 12 years (both in and out of teaching), and that they should be measured on at least six occasions during this period. We also recommend that the study be replicated starting in two, if not three, base years. We welcome public comment and discussion of our proposals.