Mortality

Mortality rate is a measure of the number of deaths (in general, or due to a specific cause) in some population, scaled to the size of that population, per unit time. Mortality rate is typically expressed in units of deaths per 1000 individuals per year. Various mortality types exist:
 * Cause-specific mortality rate: number of deaths by a specific cause in a defined population in a defined period of time. No need for these people to be already sick (we look at the total population).
 * Crude (death) rate: the number of events (deaths) in a specific period divided by person years at risk (often estimated as the population at the midpoint of the total period).
 * Age-specific mortality rates: a rate for a specific age group.
 * Infant mortality rate: number of deaths in children under 1 year of age divided by the number of live births in the same period, in a specified population.
 * Perinatal mortality rate, the sum of neonatal deaths and fetal deaths (stillbirths) per 1000 births.
 * Maternal mortality rate: number of maternal deaths by the number of women-years in the reproductive age (15-49). Maternal deaths are defined as "The death of a woman while pregnant or within 42 days from the end of the pregnancy from any cause related to or aggravated by the pregnancy or its management but not from accidental or incidental causes".