How is crude mortality rate calculated?

• A. Crude mortality rate = (deaths in a defined period / mid-year population) × 100,000.
• B. Crude mortality rate = (deaths in a defined period / total population) × 100,000.
• C. Crude mortality rate = (births / population) × 100,000.
• D. Crude mortality rate = (deaths in a defined period / mid-year population) × 1,000,000.

Answer: (A)

Crude mortality rate expresses deaths in a defined period relative to the population at risk, scaled to a standard population size so we can compare across groups. The well-established approach uses the mid-year population as the denominator because it best represents the population present throughout the year, balancing out seasonal or short-term changes. The number of deaths in the period is the numerator, and multiplying by 100,000 puts the rate on a common scale so you can compare different areas or times easily. Using the total population instead of the mid-year figure can distort the rate if population changes during the year. Asking about births would measure fertility, not mortality, and using a multiplier of 1,000,000 would yield a rate per million, which is not the standard public health convention. So the standard formula is (deaths in a defined period / mid-year population) × 100,000.