net reproduction rate

{{short description|Average number of daughters per woman with typical mortality rates}}

{{About|the average number of offspring born to a female|the rate of spread of an epidemic|Basic reproduction number}}

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.{{cite web |url=http://www.planetwire.org/details/62 |title=Glossary: Net Reproduction Rate (NRR) |website=planetwire.org |access-date=August 28, 2007 |archive-url=https://web.archive.org/web/20070224163842/http://www.planetwire.org/details/62 |archive-date=February 24, 2007 }}{{cite book|last=Dharmalingham|first=A.|title=The Methods and Materials of Demography|editor=David Swanson |editor2=Jacob S. Siegel |editor3=Henry S. Shryock|publisher=Emerald Group Publishing|date=2004|edition=2|page=819|chapter=Reproductivity|isbn=0-12-641955-8}} If the R₀ is less than one, the reproductive performance of the population is below replacement level.{{cn|date=May 2024}}

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.{{cn|date=May 2024}}

The current (2015–20) estimate for the R₀ worldwide under the UN's medium variant model is 1.09 daughters per woman.{{Cite web|url=http://data.un.org/Data.aspx?d=PopDiv&f=variableID:48|title=UNdata {{!}} record view {{!}} Net reproduction rate (surviving daughters per woman)|website=data.un.org|access-date=2019-12-14}}