Research using longitudinal data from the developed world has demonstrated the value of panel surveys for understanding an array of fundamental questions pertaining to children and young adults. Long running panels from developing countries, however, are few and far between. The Indonesia Family Life Survey (IFLS) is one such survey, and it has been valuable resource for researchers interested in studying children and young adults in low income settings. To date we have collected three full rounds of data, in 1993, 1997, and 2000. All are in the public domain, and in combination have proved highly useful with regard to enhancing our understanding of important economic, demographic, and health behaviors and outcomes. We propose to conduct a fourth full round of IFLS in 2006. This project, "Dynamics of Family Well- Being in a Low-Income Setting", will put into the public domain a fourth wave of data on children and young adults in Indonesia covering a 13 year period since 1993, and longer with retrospective information. This will represent one of the longest running socio-economic panel data sets on children and young adults in a developing country. With the longer panel, researchers will be able to better explore many topics, such as examining the transitions from childhood to adolescence, and from adolescence to young adulthood. The relevant data will include longitudinal health information of the sort that is not usually present in long social science panels. This will enable researchers to examine how health outcomes in early childhood, for example, are related to health and to non-health outcomes in adolescence. IFLS4 builds on a very well-developed set of questionnaires and field protocols from past IFLS surveys. We will add new measures to the already innovative set of physical health measures and biomarkers collected in past waves, and we will develop modules for the community-facility surveys that allow assessment of how a recent and major decentralization of social services has affected the quality, price, and availability of health and schooling services. Finally, we will continue a number of field-related methodological innovations implemented in previous waves that dramatically raised the quality of the surveys. Fundamental to these are methods of tracking households to ensure high follow-up rates (they were 94 percent and 95 percent, respectively in IFLS2 and 3).