PAPP101 - S04: Measuring fertility

Age-specific Fertility Rates

To examine fertility in detail it is necessary to construct age-specific fertility rates (ASFRs). These are simply fertility rates limited to certain age-groups of women. The groups could be of any width, or single years of age, but the convention is to form seven 5-year age groups, which cover the range 15-49 years. One can add an eighth group of 10-14 year old women but usually there are very few births in this range and it adds little advantage – but be aware that it can be done.

The construction of the first rate of the series would be:

Age - specific fertility rate 15 - 19 =	births to women aged 15 - 19 in a stated period
	number of women aged 15 - 19 in the same period

and the other six rates would be constructed accordingly. Quite often they are expressed per thousand women i.e. multiplied by 1,000 but this is not essential.

We now have seven or eight separate rates which show how fertility is distributed across the age range. Some examples are listed in Table 1.

	Age-specific fertility rates (births per thousand women)
Country	15-19	20-24	25-29	30-34	35-39	40-44	45-49
Brazil	75.6	111.9	92.8	56.8	30.5	10.4	2.0
China	8.4	142.5	120.3	41.8	10.6	3.4	0.9
Cuba	45.2	92.2	82.1	53.4	22.6	4.2	0.2
Ethiopia	72.4	198.2	243.2	202.3	122.8	58.9	22.3
Fiji	45.2	176.5	153.7	98.2	54.9	18.1	3.4
India	86.3	215.3	142.4	65.5	26.4	7.5	1.7
Indonesia	45.1	114.1	115.8	90.2	51.9	16.2	4.7
Japan	5.0	36.1	85.5	90.2	40.9	6.2	0.2
Morocco	15.1	83.1	122.9	131.1	84.8	30.2	8.0
Netherlands	5.1	38.1	107.0	131.7	58.2	8.6	0.3
Niger	207.1	304.2	304.2	269.5	202.9	105.4	45.6
Republic of Korea	2.3	19.2	102.8	102.5	27.5	3.0	0.2
Russian Federation	30.0	90.5	86.7	54.2	22.4	3.8	0.2
Rwanda	38.7	209.7	275.4	243.0	200.7	99.7	18.8
Saudi Arabia	11.6	70.9	217.5	122.4	106.0	53.0	23.7
United Kingdom	29.6	62.1	100.5	112.0	51.6	9.8	0.3
Zimbabwe	64.6	184.3	172.7	128.9	86.5	43.7	13.2

Table 1: Age-specific fertility for selected countries 2005-10

Source: Stat-Compiler