E.G.: substance abuse, teen pregnancy, strong families, academic failure, depression

Incidence is the number of new cases of a disorder that come into being at a point in time. Incidence rate is the number per specified unit of population.
Prevalence is the total number of cases at a point in time. It is a census count. Prevalence=Incidence x Duration.

Most of our interventions are prevalence oriented. To reduce the existing number by attacking duration of the disturbance (shortening it) or making the disturbance more manageable. Does nothing to address onset.