Incidence or Incidents?

What Is the Difference between "Incidence" and "Incidents"?

"Incidence" and "incidents" are easy to confuse because they sound identical (i.e., they are perfect homonyms). However, their meanings are very different.

• "Incidence" is the number of new cases of disease (e.g., a coronavirus, COVID-19, the flu, the measles) or injury in a population over a specified period of time. (More below)
• An "incident" is an event. The plural is "incidents."

Incidence

The noun "incidence" was rare before the COVID-19 pandemic. "Incidence" is a technical word used in the field disease control. It refers to the chance of developing a new condition (usually a disease) within a specified time period.

Example sentences with "incidence":

• The chart 'Incidence of Flu by Area' shows the number of people with coronavirus and coronavirus symptoms who visited their doctor last week.
• They suffer a higher incidence of measles as they did not invest in health-care systems to deliver vaccinations effectively.

There are two main measure of incidence:

• Incidence Risk. Incidence risk is the proportion of individuals in a population (initially free of disease) who develop the disease within a specified time.
• Incidence Rate. Incidence rate is the frequency of new cases of disease in a population.

Read more about the measures of disease on "Health Knowledge."

Incidents

The word "incidents" is the plural of "incident," which means an occurrence or an event.

Example sentences with "incidents":

• There is no evidence to link the two incidents at this time.
• The police are investigating two incidents of someone shooting into occupied homes.