In places where lifetime births/​woman has been converging to 2 or lower, saving one child’s life should lead parents to avert a birth they would otherwise have. The impact of mortality drops on fertility will be nearly 1:1, so population growth will hardly change. In the increasingly exceptional locales where couples appear not to limit fertility much, such as Niger and Mali, the impact of saving a life on total births will be smaller, and may come about mainly through the biological channel of lactational amenorrhea. Here, mortality-drop-fertility-drop ratios of 1:0.5 and 1:0.33 appear more plausible.
So it looks like saving lives in low income countries decreases fertility, but still increases population size. Because of the decrease in fertility, it may be good to downgrade the cost-effectiveness. The above would suggest multiplying it by around 0.5 (= 1 − 0.5) to 0.7 (= 1 − 0.33).
Yeah, that’s more in line with what I would expect. (Except the first sentence may be a bit hasty. Many first-world couples delay parenting until their 30s. If a child dies, they may not be able to have another—esp. since a significant period of grieving may be necessary before they were even willing to.)
From the abstract of David Roodman’s paper on The Impact of Life-Saving Interventions on Fertility:
So it looks like saving lives in low income countries decreases fertility, but still increases population size. Because of the decrease in fertility, it may be good to downgrade the cost-effectiveness. The above would suggest multiplying it by around 0.5 (= 1 − 0.5) to 0.7 (= 1 − 0.33).
Yeah, that’s more in line with what I would expect. (Except the first sentence may be a bit hasty. Many first-world couples delay parenting until their 30s. If a child dies, they may not be able to have another—esp. since a significant period of grieving may be necessary before they were even willing to.)