![Natural increase, 2017 CIA World Factbook](https://upload.wikimedia.org/wikipedia/commons/d/d1/Natural_increase%2C_2017_CIA_World_Factbook.svg)
In
Demography
Demography () is the statistics, statistical study of populations, especially human beings.
Demographic analysis examines and measures the dimensions and Population dynamics, dynamics of populations; it can cover whole societies or groups ...
, the rate of natural increase (RNI), also known as natural population change, is defined as the
birth rate
The birth rate for a given period is the total number of live human births per 1,000 population divided by the length of the period in years. The number of live births is normally taken from a universal registration system for births; populati ...
minus the
death rate
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 de ...
of a particular population, over a particular time period.
It is typically expressed either as a number per 1,000 individuals in the population or as a percentage. RNI can be either positive or negative. It contrasts to
total population change by ignoring net
migration
Migration, migratory, or migrate may refer to: Human migration
* Human migration, physical movement by humans from one region to another
** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
.
This RNI gives demographers an insight into how a region's population is evolving, and these analyses can inform government attempts to shape RNI.
Examples
Suppose a population of 5,000 individuals experiences 1,150 live births and 900 deaths over the course of one year.
To show the RNI over that year as a percentage, the equation would be
(1,150 – 900) ÷ 5,000 = 0.05 = +5%
To show the RNI as a number per 1,000 individuals in the population, the equation would be
(1,150 – 900) ÷ (5,000/1,000) = 250 ÷ 5 = +50
It can also be shown as natural births per 1,000 minus deaths per 1,000
(1,150 ÷ 5) – (900 ÷ 5) = 230 – 180 = +50
To convert the RNI per 1,000 population to a percentage, divide it by 1,000. The equation would be
+50 ÷ 1,000 = 0.05 = +5%
Uses
The rate of natural increase gives demographers an idea of how a region's population is shifting over time. RNI excludes in-migration and out-migration, giving an indication of population growth based only on births and deaths. Comparing natural population change with total population change shows which is dominate for a particular region. Looking at this difference across regions reveals those that are changing mainly due to births exceeding deaths and those changing mainly due to migration. The map shows just such an analysis for the US.
![Most Influential Component of Change for US Counties That Gained Population Between 2014 and 2015](https://upload.wikimedia.org/wikipedia/commons/b/be/Most_Influential_Component_of_Change_for_US_Counties_That_Gained_Population_Between_2014_and_2015.jpg)
The trend of RNI over time can indicate what stage of the
Demographic Transition Model
In demography, demographic transition is a phenomenon and theory which refers to the historical shift from high birth rates and high death rates in societies with minimal technology, education (especially of women) and economic development, to lo ...
(DTM) a region or country is in.
National efforts to affect RNI
Government attempts to shape the RNI of a region or country are common around the world. Policies can either encourage or discourage an increase in birth rates. For example, during the COVID-19 crisis Singapore offered families a “pandemic baby bonus” to encourage a higher birth rate, therefore increasing RNI. The US has considered similar policies. Another example was China's
one-child policy
The term one-child policy () refers to a population planning initiative in China implemented between 1980 and 2015 to curb the country's population growth by restricting many families to a single child. That initiative was part of a much bro ...
, intended to decrease birth rates, therefore decreasing the RNI.
[{{Cite journal, last=Hesketh, first=Therese, last2=Lu, first2=Li, last3=Xing, first3=Zhu Wei, date=2005-09-15, title=The Effect of China's One-Child Family Policy after 25 Years, journal=New England Journal of Medicine, volume=353, issue=11, pages=1171–1176, doi=10.1056/NEJMhpr051833, issn=0028-4793, pmid=16162890, url=http://discovery.ucl.ac.uk/8938/1/8938.pdf]
A country with a good
infrastructure
Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and priv ...
to support families, women's health, and maternal/child health would likely have lower death rates from infant or maternal mortality, which would increase RNI.
See also
List of countries by natural increase
This article contains a list of countries by rate of natural increase.
Methodology
The rate of natural increase is defined as the crude birth rate minus the crude death rate. It is expressed as a rate per 1,000 population.
Countries and sub ...
Birth rate
The birth rate for a given period is the total number of live human births per 1,000 population divided by the length of the period in years. The number of live births is normally taken from a universal registration system for births; populati ...
Mortality rate
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 de ...
Population growth
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to ...
References
Demographics indicators
Natural increase
In Demography, the rate of natural increase (RNI), also known as natural population change, is defined as the birth rate minus the death rate of a particular population, over a particular time period. It is typically expressed either as a number ...
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