What is net reproduction rate

The Net Reproduction Rate (NRR) is a measure of the average number of daughters that would be born to a woman (or a group of women) if she passed through her lifetime conforming to the age-specific fertility and mortality rates of a given year. This demographic metric is used in population studies to understand the reproduction patterns and predict future changes in population size.

Here are the steps to calculate the Net Reproduction Rate:

1. Determine the Age-Specific Fertility Rate (ASFR): This is the number of births in a year to women in a particular age group divided by the number of women in that age group.

2. Determine the Age-Specific Survival Rate (lx): This is the proportion of individuals surviving to a particular age.

3. Multiply the ASFR and lx for each age group: This gives you the number of daughters born to women in each age group that survive to the mother's age.

4. Sum these values across all age groups: This gives you the total number of daughters that would be born to a woman if she were to pass through her lifetime conforming to the age-specific fertility and mortality rates of a given year.

5. The NRR is this total number divided by the number of women. If the NRR is greater than 1, the population is increasing. If it's less than 1, the population is decreasing. If it's exactly 1, the population is stable.