<unk>  is the "monitoring of rate of occurrence of specific diseases/conditions through a voluntary network of doctors, laboratories and public health departments with a view to assess the stability or change in health levels of a population". It also describes the study of disease rates in a specific cohort such as a geographic area or subgroup to estimate trends in a larger population.
Sentinel surveillance
Triage
Disease surveillance
Biomonitoring
Demographic surveillance system
Economic epidemiology
Spatial epidemiology
Life course approach