Net reproduction rate

In population ecology and demography, the net reproduction rate, R₀, is the average number of offspring (often specifically daughters) that would be born to a female if she passed through her lifetime conforming to the age-specific fertility and mortality rates of a given year. This rate is similar to the gross reproduction rate but takes into account that some females will die before completing their childbearing years. An R₀ of one means that each generation of mothers is having exactly enough daughters to replace themselves in the population. If the R₀ is less than one, the reproductive performance of the population is below replacement level.^{[citation needed]}

The R₀ is particularly relevant where sex ratios at birth are significantly affected by the use of reproductive technologies, or where life expectancy is low.^{[citation needed]}

The current (2015–20) estimate for the R₀ worldwide under the UN's medium variant model is 1.09 daughters per woman.

See also

• List of countries by net reproduction rate
• Sub-replacement fertility
• Total fertility rate