My major scientific contributions are in the areas of (1) designing, running and evaluating (often large-scale)multidisciplinary population-based randomized controlled screening trials to establish the efficacy of screening, (2)evaluating active (inter-)national screening programs and clinical tests to establish effectiveness and (3) guiding public health policies on screening and primary prevention using predictions of favourable and unfavourable effects and the cost of interventions, based on micro-simulation modelling of the natural history of disease, risk-prediction modelling and costeffectiveness and cost-utility analyses.