An ad hoc steering committee will organize a 2-day, public workshop on developing a methodological research program for longitudinal studies of the kinds supported by the National Institute on Aging (NIA). The workshop will contribute to the NIA strategic objective to “support the development of population-based data sets, especially from longitudinal studies, suitable for analysis of biological, behavioral, and social factors affecting health, well-being, and functional status through the life course.” The workshop will build on a prior CNSTAT expert meeting for NIA that discussed methods to reduce costs and respondent burden in longitudinal studies without adverse effects on data quality. Topics to be reviewed at the workshop may include: the use of alternative interview modes, multimodal approaches, and innovative designs for communication with study participants and administration of interviews; expanding the use of linkages to administrative and private sector data to add to or replace questionnaire content; optimizing the periodicity and content of current instruments for NIA-supported longitudinal studies; and developing more effective incentives to encourage study participation and reduce the number of contacts per respondent. The workshop will also discuss ways to facilitate sharing of information, lessons learned, survey questions or data structures, and personnel across longitudinal studies so that the field advances in the application of state-of-the-art methods across the board. A rapporteur will prepare a brief workshop proceedings. Presentations and other background materials for the workshop will be made available on-line.