"We have been below 2.1% for approx 34 years now. What do you see that would drive fertility above replacement levels?"

This question shows the horrible state of understanding that our experts have with respect to these population issues. This question is one that just about every demographer is willing to ask. It shows several bad assumptions.

1) Time - It assumes that if something goes well for some amount of time, then it will go fine forever. If the space shuttle works successfully for 24 launches, then we can assume that the next will be fine. It also assumes that this time factor is measured in years, not for example generations, and assumes that 34 years is a lot.

2) Selective Success - It grabs one sample set that looks good and assumes that as the normal situation. In this case the good sample is probably all countries that have a Total Fertility Rate (TFR) below 2.1 for the past 34 years. Never mind that the TFR of the USA is not looking so good lately.

3) Random limit - The expert knows that 2.1 is a magic number. A TFR above 2.1 is bad. A TFR below 2.1 is good. But nothing in the fact that the TFR has been below 2.1 for 34 years in some sample group has anything to do with 2.1. It has been below 2.2, and 2.3 and 5 also. There is nothing in the math, or stats, or sampling or anything that suggests there is a barrier at 2.1.

This is a very important concept. The demographers have provided the expert conventional wisdom on this topic, and at the core of that "wisdom" is the Demographic Transition Theory. The DTT is essentially the same bad assumptions that led to this question.

We must figure out how to get demographers to comprehend that the DTT is crap for predicting long term fertility, and we must comprehend that we don't need predictions. We need mechanisms that ensure we do not over breed.