Part 3:  Fertility

 

Spend the least amount of time analyzing and comparing Crude Birth Rates.  They are not our best measure of fertility, although their level does tend to reflect real changes in fertility, and they are a good measure of the extent to which numbers are being added to the population by births.

 

 

Spend more time analyzing the Age Specific Fertility Rate Charts.  These rates are especially useful in determining both the level and the timing of fertility in each population.  Look at the ASFRs for each population at each age group.  Which population has the higher ASFR?  How much higher is it in one population than the other?  Is the ASFR for 15-19 year olds 4 or 5 times as high in one than the other?  Now examine the timing of child bearing.   Do women start childbearing at a young age or wait until they are older?  The easiest way to examine timing is to analyze the "% of all fertility" figures and relate how much greater that percentage is for a less developed population's 15-19 year-olds than for your more developed population's 15-19 year olds.  For which age group is the % highest in each of your populations?  In which population do older women contribute a higher % of total fertility?  

 

 

 

Take a look at the Age Specific Fertility Rate Chart for 1995-2000 and compare the levels to those in the 2000-2005 chart.  Is fertility declining?  Is it declining across all age groups? 

 

 

 

Spend the most time analyzing trends in the Total Fertility Rate.  The TFR is derived from age specific fertility rates and is the best single measure of fertility.  The age specific rates are divided by 1000 and then applied to a hypothetical woman for each of her reproductive years from age 15 to age 49.  The result is an easy to understand "children per woman" measure.  A TFR of 3.1 means that the age specific fertility rates in effect in a particular year imply that a woman experiencing them through out her reproductive years would have 3.1 children.  Examining its level over time is the easiest way of determining fertility change in a population.  It is also our best single comparative measure of fertility.  You can directly compare the TFRs of your two populations to determine how much higher fertility is in one population than the other.  If the TFR of one population is 2 and that of another population is 4, then the fertility of the second population is really twice as high as the first. Check the level of each population's Total Fertility Rate to see if it is below "replacement level" -- that is if each woman is having less than the 2.1 children needed to "replace" herself and her partner.

 

 

 

Examine the Annual % Change in TFR chart   See if there is a clear pattern of change, especially over the last ten to fifteen years.  You will need this analysis when it comes times for you to project future changes in the Total Fertility Rate

 

 

 

The Net Reproduction Rate chart offers an even more sophisticated measure of "replacement."  See how many daughters will survive long enough to have children themselves.  A Net Reproduction Rate of "1" means that each woman is just replacing herself -having exactly one daughter who will survive through her own reproductive years.  If fertility is below replacement -- measured either with the TFR of the NRR -- this chart will reveal how long this has been going on.