Mortality is best described as which of the following?

• A. The number of deaths in a population during a specified period
• B. The number of existing cases in a population at a point in time
• C. The rate at which new cases occur
• D. The ratio of sick to well persons

Answer: (A)

Mortality is the measure of deaths that occur in a defined population during a specific time frame. This focuses on the event of death within that population and period, which is distinct from how many people have a disease at a given moment (prevalence) or how quickly new disease cases arise (incidence). It also isn’t about the ratio of sick to well people, which is a different way to describe disease burden. In practice, mortality can be expressed as a count of deaths in the period (and sometimes as a mortality rate), but the option here best matches the simple count of deaths during the specified time.