Lab #5: Fertility

 

We have discussed several different measures of fertility, each of which is more specific in terms of the number of births relative to the population “at risk” of giving birth.  In this lab, you will be using data published by the National Center for Health Statistics of the Center for Disease Control to compute these measures. 

 

Crude Birth Rate

The Crude Birth Rate is the simplest form of describing fertility in a culture, but its primary uses are to compute rates of natural increase and momentum factors.  The CBR does not really tell you much about how many children a typical family has.  It has another inherent weakness.  It uses the entire population as the denominator, thus including all males and all females not in their childbearing years.

 

CBR = #live births/Total Population x 1000

 

General Fertility Rate

The General Fertility Rate begins to control for population structure by computing the number of live births for the population of women in their childbearing years per thousand.  It is similar to the CBR, but the denominator is the at risk population only.

 

GFR = # live births//Population females (10-49 or 54) depending on how a country reports its statistics x 1000.

 

Age-Specific Fertility Rate

The Age-Specific Fertility Rate is similar to the age-specific mortality rate in that it measures how many births there are to women in specific age cohorts.  This is a helpful statistic in understanding what the typical childbearing age is in a culture.  The age cohort(s) with the highest rate(s) tell you when childbearing most commonly occurs in a woman’s life in that culture.

 

ASFR = # live births to women in an age cohort/Population of women in that age cohort x1000

 

Total Fertility Rate

The Total Fertility Rate or TFR is the most powerful and useful measure of fertility in understanding a population.  It represents the number of children the typical woman in that population will have over her childbearing years, based on 2 assumptions:

 

  1. Women will have the same birth rates over their lifetimes as women in different age cohorts in that same population have had in that year; and
  2. Women will survive through their childbearing years.

 

TFR = (h S AFSR)/1000

Where h=the number of years in the age cohorts for the ASFR.

 

Using the data below, compute the CBR, GFR, ASFRs and TFR for the US for the year 2007. Compare and contrast the rates for women of all races, non-Hispanic Whites, non-Hispanic Blacks, and Hispanics. Remember, Hispanics can be of any race. Although 2 of the tables combine ages 45-54, still use h=5 in computing TFR.

 
Table 1. Total Population, Female Population, and Births, All Races, 2007
         
  Estimated Population Births    
Total: 301,621,159 4,317,119    
Female:        
10 to 14 years 9,909,709 6,218    
15 to 19 years 10,633,131 445,045    
20 to 24 years 10,129,537 1,082,837    
25 to 29 years 10,118,017 1,208,504    
30 to 34 years 9,562,403 962,179    
35 to 39 years 10,547,424 499,916    
40 to 44 years 11,127,618 105,071    
45 to 49 years 11,576,913 5,145    
50 to 54 years 10,714,061 2,205    
Source: American Community Survey 2007 estimate, National Vital Statistics Reports 57(12):7-8.
         
Table 2. Total Population, Female Population, and Births, Non-Hispanic Whites, 2007
  Estimated Population Births    
Total: 223,005,483 2,312,473    
Female:        
10 to 14 years 6,763,071 1,269    
15 to 19 years 7,340,235 173,104    
20 to 24 years 7,124,658 526,943    
25 to 29 years 7,086,851 676,599    
30 to 34 years 6,565,805 566,197    
35 to 44 years 15,634,080 301,666    
45 to 54 years 17,093,758 4,544    
Source: American Community Survey 2007 estimate, National Vital Statistics Reports 57(12):7-8.
         
Table 3. Total Population, Female Population, and Births, Non-Hispanic Blacks, 2007
         
  Estimated Population Births    
Total: 37,334,570 627,230    
Female:        
10 to 14 years 1,482,902 106,224    
15 to 19 years 1,648,902 200,273    
20 to 24 years 1,464,927 157,173    
25 to 29 years 1,400,868 97,332    
30 to 34 years 1,290,303 50,614    
35 to 44 years 2,877,988 12,428    
45 to 54 years 2,745,799 860    
Source: American Community Survey 2007 estimate, National Vital Statistics Reports 57(12):7-8.
         
Table 4. Total Population, Female Population, and Births, Hispanics, 2007
  Estimated Population Births    
Total: 45,427,437 1,061,970    
Female:        
10 to 14 years 1,939,838 2,407    
15 to 19 years 1,844,325 148,453    
20 to 24 years 1,709,556 305,107    
25 to 29 years 1,823,312 287,730    
30 to 34 years 1,808,993 201,212    
35 to 44 years 3,233,136 95,694    
45 to 49 years 1,209,273 20,273    
50 to 54 years 1,116,252 1,095    
Source: American Community Survey 2007 estimate, National Vital Statistics Reports 57(12):7-8.