1. Calculating population change… What factors do you need to take into account when calculating population growth?

2. Population dynamics Learning outcomes You should all be able to: Identify the different factors that affect a change in population size. Most of you should be able to: Calculate “crude birth rate, crude death rate, fertility, doubling time and natural increase rate”. Some of you might be able to: Explain different values of “crude birth rate, crude death rate, fertility, doubling time and natural increase rate” from given data.

3. Measure of population change Crude birth rate Crude death rate Fertility Doubling rate Natural increase rate

4. Crude Birth Rate Calculate the following CBR: USA, 2005 Births: 4,138,349 Total population: 295,895,897 CBR = ? 13.98 per thousand Total number of births Total population X 1000 CBR = What is Crude Birth Rate? The number of live births per 1000 people in a population. It does not take into account the age and sex structure of the population.

5. Crude Death Rate How do you think it is calculated? Total number of deaths Total population X 1000 CDR = Calculate the following CDR: USA, 2005 Deaths: 2,448,017 Total population: 295,895,897 CDR = ? 8.27 per thousand

6. Fertility Rate Total Fertility Rate is the average number of children each woman has over a lifetime. Fertility Rate is the number of births per thousand women of child-bearing age. Sometimes used as a synonym for birth rate. However fertility rate focuses on the number of births per 1000 women and birth rate looks at the entire population. Total number of births Number of women of child-bearing age X 1000 Fertility rate =

7. Natural Increase Rate The difference between the number of live births and deaths occurring in a year. Measures the population change but does not include the effects of migration. How would you calculate this? Crude Birth Rate – Crude Death Rate 10 NIR % = What was the NIR for the USA in 2005? 0.57% (13.98 – 8.27) = 10

8. Doubling Time 70 Natural Increase Rate Doubling time (years) = The time in years that it takes a population to double. If you have an NIR of 1% what will the doubling time be? What was the doubling time of the US in 2005? 70 / 0.57 = 122.8 years

9. On the worksheet Fill in the blank spaces using the calculations that we have just seen.