Fertility

Question 1

Crude birth rate

Answer 1

CBR = (B/P) *1000, where:

B = # live births in a year
P = mid-year population

Question 2

General fertility rate

Answer 2

GFR = (B / F15-49) *1000, where:

B = # live births in a year
F15-49 = mid-year female population aged 15-49

Question 3

Age-specific fertility rate

Answer 3

ASFR = (Bx / Fx) *1000, where:

Bx = # live births in a year to women aged x
Fx = mid-year female population in aged x
x = single year of age, 5-year age group, etc.

Question 4

Age-sex adjusted birth rate (direct method)

Answer 4

((Sum fa*Pfa) / P) *1000, where:

fa = age-specific birth rates for particular population
Pfa = female population in standard population
P = total standard population

Question 5

Age-sex adjusted birth rate (indirect method)

Answer 5

(b / (Sum Fa*pfa)) *CBR, where:

b = total births for particular population
pfa = females by age for particular population
Fa = age-specific birth rates for standard population
CBR = crude birth rate for standard population

Question 6

Total fertility rate

Answer 6

TFR = (Sum Bx/Fx) *1000, where:

Bx = # births in a year to women aged x
Fx = mid-year female population of same age
x = single year of age, 5-year age, etc. 

TFR = Sum(ASFR) -> single-year age group
TFR = 5* Sum(ASFR) -> 5-year age group

Question 7

Child-woman ratio

Answer 7

CWR = (P0-4 / F15-49) *1000, where:

P0-4 = # children aged 0-4
F15-49 = # females aged 15-49

Question 8

Gross reproduction rate

Answer 8

GRR = (Sum Bfx/Fx) *k, where:

Bfx = # female births in a year to women aged x
Fx = mid-year female population of same age (lower & upper limits of the child bearing age)
k = constant

Note: For 5-year age groups, multiple equation x5.

Note: Alternative is Bx for total births; multiply entire equation by Bf/Bt = proportion of total births that are female.

Question 9

Net reproduction rate

Answer 9

NRR = Sum((Bfx/Fx) * (Lx/l0)) *k, where:

Bx/Fx = age specific fertility (female births only) rate at age x
Lx/l0 = life table survival rate

Note: For 5-year age groups, multiple equation x5.

Note: Alternative is Bx for total births; multiply entire equation by Bf/Bt = proportion of total births that are female.