Week 3: Fertility

Question 1

Name the two different approaches of measuring fertility.

Answer 1

• Period fertility analysis
• Cohort fertility analysis

Question 2

How does period fertility analysis measure fertility?

Answer 2

Looks at fertility cross-sectionally - births over a defined period (usually one year) .

Question 3

How does cohort fertility analysis measure fertility?

Answer 3

Looks at fertility longitudinally - births to specific cohort of women (e.g. a birth cohort or marriage cohort) over their lifetime.

Question 4

Give a measure of period fertility.

Answer 4

Crude Birth Rate (CBR)

Question 5

How is the Crude Birth Rate calculated?

Answer 5

births for one year/ mid-year population (* 1000)

Question 6

How is the General Fertility Rate (GFR) calculated?

Answer 6

births for one year / mid-year population of women aged 15-44(9)

Question 7

How are Age-Specific Fertility Rates (ASFR) calculated?

Answer 7

births to women aged x / mid-year pop of women aged x

Question 8

What are the disadvantages of ASFR?

Answer 8

• Requires more data than CBR or GFR (births by age of mother)
• Usually presented for 5-year groups

Question 9

What is the Period Total Fertility Rate (PTFR)?

Answer 9

A single measure that describes the average number of births a woman would have in her life if she experienced the current ASFRs of the population.

Question 10

How do we calculate PTFR?

Answer 10

(Sum of ASFRs x 5)/1,000

Question 11

List the two conditions for calculated PTFR.

Answer 11

• Multiply by 5 only if ASFRs are for 5-year age group
• Divide by 1,000 only if ASFRs calculated per 1,000

Question 12

What is the Total Fertility Rate (TFR)?

Answer 12

The number of children a women would have if:
- she survived through reproductive years (to age 50)
over her life
- she experienced the ASFRs for the year in question
i.e. the TFR is not a measure of actual fertility in the population - it refers to a synthetic (hypothetical) cohort of women

Question 13

What is the Gross Reproduction Rates (GRR)?

Answer 13

The TFR restricted to female births.

Question 14

How do we calculate the Net Reproduction Rate (NRR) by adjusting for mortality?

Answer 14

NRR = GRR * probability of surviving to age m
- m is the mean age of the age specific fertility distribution
- higher the mortality, greater difference between GRR & NRR

Question 15

What is the Cohort Total Fertility Rate (CTFR)?

Answer 15

Average number of births a member of cohort would have if they reached age 50