What is incidence?
incidence is The number of cases of disease, infection or some other event having their onset during a prescribed period of time. It is often expressed as a rate (for example, the incidence of cardiovascular disease per 1000 population aged 65-74 years during a specified year). Incidence is a measure of morbidity or other events that occur within a specified period of time.
source: A GLOSSARY OF TERMS FOR COMMUNITY HEALTH CARE AND SERVICES FOR OLDER PERSONS. World Health Organization, 2004.