Mortality rate, or
death rate, is a
measure of the number of
deaths (in general, or due to a specific cause) in a particular
population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of deaths per 1,000 individuals per year; thus, a mortality rate of 9.5 (out of 1,000) in a population of 1,000 would mean 9.5 deaths per year in that entire population, or 0.95% out of the total. It is distinct from the so-called "
morbidity rate" (a vague term sometimes used to refer to either the
prevalence or
incidence of a disease), and also from the
incidence rate (the number of newly appearing cases of the disease per unit of time).