Chang Ming-cheng adopts the following metaphor: Population control is not like turning off a tap, where people have children when you want them to, and don't when you don't want them to. Especially today, when the idea of population control is already deeply imprinted on people's consciousness, the population will not dramatically increase because of a few incentives.
家計所長張明正就比喻，控制人口不是關水龍頭，你要他生就生，要他不生就不生，尤其在節育觀念已深入人心的今天，不會因為一些誘因，人口就會劇增。