Cumulative incidence provides an estimate of the risk that a person will experience an event or develop a disease during a specified period of time. It is calculated as the number of new events or cases of disease that develop in a population at risk during a specific time interval. Cumulative incidence (also referred to as cumulative incidence or incidence proportion) allows researchers to predict risk of a disease or event over a year, 10 years, or even a lifetime; this time period must always be specified when the cumulative incidence is reported.

One example of cumulative incidence is the risk of developing flu among seniors vaccinated against influenza. Another would be the proportion of passengers who develop gastroenteritis while vacationing on a commercial cruise ship ...