Our research group focus is in on outcomes and epidemiologic research in older populations. A major focus of our work has been on establishing the empiric and conceptual basis for prognostic stratification in the elderly. We have identified key determinants of major health outcomes such as disability, nursing home placement, and death in the elderly. In addition we have established hospitalization as an important mediator of disability in the elderly and demonstrated that the development of disability following hospitalization is best explained by an integrative model that considers disease, psychological, and social factors. An important component of our work has been establishing the place of functional and disability measures in prognostic systems. We have conducted a series of studies demonstrating that functional status measures are fundamental determinants of health outcomes and that functional status can be used in bedside risk stratification tools. For example, we have demonstrated that functional status is the strongest predictor of 1-year mortality in hospitalized elders after discharge. We have also demonstrated that integrative measures of functioning predict 4 year health outcomes in community-living elders.