The total Fertility price (TFR) is a standard demographic indicator used around the world to estimate the average number of children that a woman would have actually over she childbearing year (i.e. Period 15-49), based on existing birth trends.

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It is calculation by including up the average number of births every woman throughout five-year age groups (i.e. Age-specific fertility rates, or ASFR). The details formula to calculate TFR is:


More info on exactly how TFR is calculated is available at the room of Statistics’ website.

What this way is the there are two an essential components that affect TFR:

The number of births because that each period group of women (in the numerator), and also The number of women in each age group (in the denominator).

Does an increase in births mean that TFR will definitely go up?

An increase in the number of births does no necessarily lead to boost in TFR. Whether TFR will boost depends not only on the variety of births (numerator), but likewise on the number of women in the childbearing age groups (denominator). Thus, even if over there are more births, TFR might not rise if there room also an ext women in the childbearing age groups.

We it was observed this phenomenon in 2017-2019, where the number of Singapore citizens births boosted (for example, there to be 32,844 births in 2019 compared to 32,356 births in 2017,), yet TFR declined to 1.14 in 2019, indigenous 1.16 in 2017. While over there were more babies, the number of women beginning the height child-bearing period groups (25-39 years) had additionally risen. These women were born in the decade beginning from 1988, and also many of castle are kids of the infant Boomer generation. Contrasted to previously cohorts, an ext of lock were no yet married or had not started having kids yet.

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Does the variety of marriages or age at marriage/ birth impact TFR?

From the formula above, we have the right to see that the number of marriages walk not directly influence TFR, since it is no in the numerator or the denominator. Similarly, TFR is not directly influenced by the period at very first marriage or period at first birth. What is more important is the variety of births women have actually on average, nevertheless of the period at i beg your pardon they gain married or have children. However, there might be indirect effects, as data in Singapore mirrors that females who gain married and also start having children earlier tend to have more children over your lifetime.