Sam Hyun Yoo

Sam Hyun Yoo demonstrated that delayed childbearing as well as a reduced number of births per woman is affecting fertility in the Republic of Korea.

The tempo effect is a change in the period Total Fertility Rate (TFR) caused by a change in the timing of childbearing. East Asian countries have experienced low TFRs recently, but it is still unclear whether the tempo effect depressed TFRs. I test whether the ultra-low fertility reflects a delay in childbearing (fertility tempo), a decline in the number of births per woman (fertility quantum), or both.

For the undistorted measure of period fertility, I apply the Bongaarts and Sobotka method to the Republic of Korea. The results show that the tempo effect has significantly lowered the period TFR in Korea since the early 1980s. The tempo distortion peaked in the early 2000s when the country’s TFR dropped below 1.3. The decline in the period TFR was driven by the delay in childbearing in the 1990s, but was followed by a decline in fertility quantum from 2000 onwards, notably in lower-order births. As a result, the fertility quantum shows a downward trend, although the trend in the period TFRs has been stabilized for the last decade. The undistorted TFR is also expected to decline further over the next two decades at least, unless the trends in quantum and tempo effects are immediately reversed in the coming years.

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Funding: IIASA Postdoctoral Program

Nationality: South Korean

Program: World Population Program

Dates: June 2015 – February 2017

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Last edited: 29 August 2017


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