This research seeks an understanding of adjustments made in housing as they are influenced by circumstances of aging. Using a fully specified model, the study will isolate the determinants of in-place adjustments, such as modifying the current dwelling through alterations or additions, performing various repairs and maintenance, or changing the use of rooms. A dynamic formulation of the adjustment process will be employed; data covering 52 months will include home improvement logs and yearly household interviews. Two years of already existing data will be combined with new information using an existing random sample of homeowners. To permit comparisons, both elderly and non-elderly households will be surveyed. Previous studies of in-place adjustments are few and are characterized by three basic shortcomings: (1) they are static rather than dynamic; (2) they model household decisions relating to in-place adjustments independently rather than simultaneously; (3) they are under-specified. This project will involve a formulation which is dynamic with simultaneous estimation, and with a full range of variables suggested by the economic and sociological literature. Each determinant of in-place adjustments is incorporated in a demand and supply framework, although the choice of variables relies heavily on theories of moving behavior provided by sociologists and geographers. The model to be employed takes into account income, age of head and household composition, as suggested by previous studies. Levels of social interaction, receipt of support services (both formal and informal) and proximity of informal suppliers are also measured. The health status and physical limitations of household members may well influence adjustment behavior and are accounted for in the research design. Lastly, because housing is an investment as well as a consumption good, neighborhood conditions are measured. Underlying this study is the conception of the aging process as marked by changing needs for various goods and services at each stage of the life cycle. Understanding housing should provide insights into other adjustments. Greater knowledge of these processes will contribute substantially to the ability to forestall institutionalization and encourage independent living by the elderly.