Common sense would indicate that the replacement level fertility of Norway ought to be lower than that of Sudan due to fewer children dying there. Why, then, is the replacement fertility rate universally taken as 2.1?

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    $\begingroup$ Although you might find some reference that uses that number as a base level, it is incorrect to say that it is "universally taken as 2.1" and yes obviously varies with mortality. 2.1 refers to developed countries, which are typically the ones near replacement level, and which have fairly consistent mortality. $\endgroup$
    – Bryan Krause
    Aug 20, 2019 at 20:24
  • $\begingroup$ I was referring to this article livemint.com/news/india/… about India, which says that the fertility rate of India is 2.2 at present. Isn't it safe to say that it is already below replacement level? $\endgroup$
    – Siddhartha
    Aug 20, 2019 at 20:31
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    $\begingroup$ I don't know who livemint is but they don't look like a scientific publication. prb.org/wp-content/uploads/2015/09/… gives replacement level of 2.23 for India versus 2.06 in Europe. I'd expect there is a lot of regional variation within India. $\endgroup$ Aug 20, 2019 at 20:47

1 Answer 1


Your claim that the replacement level fertility is "universally taken as 2.1" is false.

World Resources Institute:

This rate is roughly 2.1 children per woman for most countries, although it may modestly vary with mortality rates.

Craig (1994):

In developed countries, replacement level fertility can be taken as requiring an average of 2.1 children per woman. In countries with high infant and child mortality rates, however, the average number of births may need to be much higher.

2.1 is simply a very crude and made-up figure. It's just 2 (replace the parents) plus a little more (arbitrarily assumed to be 0.1) to account for mortality.

Where a writer is unable or unwilling to obtain better estimates, she will often simply use this 2.1 figure. But this does not mean she believes that the true replacement level fertility in her context is precisely 2.1.


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