Prediction research Introduction and examples A. Cecile J.W. Janssens, PhD Professor of Translational Epidemiology

Prediction research There is increasing interest for differentiating preventive interventions to specific risks groups rather than to a risk population at large. Such targeted strategies require that risk populations can be distinguished, which is a challenging prediction problem when multiple risk factors are simultaneously considered. This course is about methodology of prediction research. You will learn how prediction research is performed and what the essential topics in prediction research are. The course will cover the specification of the public health scenario (what is to be predicted in whom for what purpose), the key parameters in the study design, the practical development of risk models, the quantification of its performance and the critical assessment of the predictive ability and usefulness of the risk model.

My introduction My expertise: methodology of genetic risk prediction My interest: methodology and analyses of prediction research and assessment of risk model, though more the ‘why’ than the ‘how’: - What methods/stats is most appropriate for the research question? - What do the findings (really) mean?

My expertise

Introduction What are your expectations? What do you hope to learn? What is your public health interest? e.g., diabetes prevention, infectious diseases, exercise promotion, health economics... (  I am asking to target my examples and illustrations)

The quality of the course is up to us... Participation Satisfaction Listening + asking

What is prediction?

Specific outcome One or more predictors A probability concept Time aspect: (often but not always) statement about the future time  t0 OutcomePredictor(s)

Why prediction research? Not better understanding of disease process, but assist in medical decision making Inform about risk of disease or prognosis Assist in medical decision making: -Intervention or not -Types of intervention (medication / surgery) -Dose and frequency of intervention e.g. screening intervals, medication dose

Prediction versus association (statistical) Association: any relationship between two variables Prediction: a different way of expressing the relationship between a risk factor and disease But: Prediction requires association Association does not always lead to prediction AssociationPrediction X Why and why not?