The focus of this research programme is on prediction and evaluation of the effects of interventions on morbidity and mortality in their target populations, and on relating these health effects to economic consequences in cost-effectiveness studies. The research programme is broken down into: - Secondary prevention. Three types of study are undertaken: (1) The prospective evaluation of screening strategies, with emphasis on impact on morbidity and mortality and on cost-effectiveness ratios. (2) Monitoring and evaluation of ongoing screening programmes. (3) Analysis of new developments and research questions. - Tropical disease control programmes. Research is focused on development and validation of epidemiological models (ONCHOSIM, LYMFASIM, SCHISTOSIM, SIMLEP, STDSIM) which are applied to evaluate the impact of control measures on transmission, morbidity and mortality of a number of important tropical infection diseases. - Interventions in clinical populations. Three questions are studied: what is wrong with the patients? (diagnostics), what can be done about it? (therapy choice), and what will happen? (prognosis). Emphasis is on studying prognosis. - Medical decisions concerning the end of life. Aim of this research programme is to describe the occurrence, backgrounds and decision-making progress for euthanasia, physician-assisted suicide, and other medical decisions concerning the end of life. Specific fields of interest are neonatology and psychiatric practice. - Trends in population health. Changes in population health status and health care costs as a consequence of changes in medical care and risk factor exposure. - Methodological issues, including: development and application of dynamic age-structured population health models, standardization of research methodology with respect to descriptive health status measurement, and methodological aspects of microsimulation modelling, an approach which is often applied in this research programme.