Bongaarts與Feeney(1998)指出生育步調(tempo effect)會扭曲時期別總生育率(TFR),也就是說生育步調延後對TFR有壓低的作用。因此,目前低生育率國家之實際生育水準應該高於TFR,當生育的時間效果減緩或停止時,TFR有可能止跌回升。Lutz與Skirebekk(2005)應用Bongaarts等人的觀點,反向運用生育的時間效果,企圖透過改變既有社會制度來促使個人生育步調提前,以達提升TFR的目的,具體建議包括提前入學、縮短高等教育年限等,可稱之爲生育步調政策(tempo policy)。台灣於2003年成爲「超低生育率(lowest-low fertility)」國家,2005年的總生育率更降至千分之1110,欲儘快使生育率止跌回升,調整生育步調是一個值得思考的方向,本文應用Bongaarts與Feeney的方法,模擬生育步調提前對TFR的影響,結果顯示即便生育步調只有些微提前,對於提高TFR都有明顯幫助。
Postponed childbearing will deflate the period Total Fertility Rate (TFR), but once the postponement stops, the fertility rate will return to a higher ”purer” level (Bongaarts and Feeney, 1998). Pursuing this line of thinking Luts and Skirebekk (2005) explore how an increase in fertility may be effected by shifting downward of fertility tempo through modifications of existent social institutions, such as earlier entrance into school and the shortening of time limit for higher education. Such attempts may be called tempo policies. Taiwan became the lowest-low fertility region in 2003 and the TFR in 2005 dropped to as low as 1.11. If we hope to raise the fertility of the population, such tempo policies deserve our serious consideration. Applying the model of Bongaarts and Feeney, we simulate the effect of downward shift of fertility on the TFR. The results show that even a slight shift downward of fertility tempo could substantially raise the TFR of the population.