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The conventional wisdom of demographers is fundamentally flawed.

In the conversation "Why do so many think that population growth is an important issue for the environment? Don't they know the facts of demographics?" Hans Rosling uses the "facts" of demography to argue we don't have to worry about population growth. Demographers have fundamental flaws in their thinking. In short, they are dead wrong.

Consider a belief that has these 2 characteristics: 1) believers average more than 2 children, and 2) they successfully pass along that belief to the next generation to at an average of at least 2 of those children. This belief will overpopulate the planet. Imagine that 99% of the population are non-believers, and 1% are believers. It would take many generations for the believers to rise to sufficient numbers so that demographers would notice them, but in the end, the birth rate will be determined by the believers.

This logic shows us flaws in the data collection and interpretation techniques that demographers use. Demographers must prove that these belief characteristics cannot exist if there is any hope that the downward trend of birth rates will continue and stay at or below an average of 2 children.

Their sampling techniques filter out beliefs that are passed to the next generation. This error means that if demographers tried to find groups that have beliefs that are not behaving according to the demographic transition predictions, they won't find them in their data.

Demographers use extrapolation techniques to predict future birth rates, but the logic dictates that they must find groups that are averaging the most children, and monitor their growth.


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    Apr 22 2012: Do you have a specific example of an error by demographers? How are they "dead wrong"?
    • Apr 23 2012: I reread my original posting, and it seems to me that I did provide an example.
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        Apr 26 2012: I reread your original post and it seems to me that you pawn off hypotheticals as examples. Also, your conclusion in the hypothetical is unfounded, confusing totals with ratios.

        You claim demographers are dead wrong. If they are dead wrong then a clear-cut example should be easy for you to come up with. Not some what-if scenario, but an actual claim made by demographers which you show to be wrong, or at least biased due to an obvious confounding factor.
        • Apr 27 2012: I don't follow your hypothetical example complaint. Please be specific.

          I thought that "Demographers use extrapolation techniques to predict future birth rates, but the logic dictates that they must find groups that are averaging the most children, and monitor their growth." is a clear-cut example. I have not been able to find any articles that state that some group has a belief with the two characteristics described above, or an article that proves it cannot exist.

          Hans Rosling's TED Talk referenced above, shows the audience how birth rates have come down as wealth has risen. This theory, the demographic transition theory, depends on extrapolation and totally ignores the possibility that this topic brings up.

          This concept is simply absent in demography. That makes their conclusions dead wrong.

          I would be thrilled to find a demographer that comprehends this concept. Please introduce me to them.
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        Apr 27 2012: I might have misread your example. I took the belief to be arbitrary with the assumed >2 birth rates to imply the spread of the belief. In this case, non-belief could have a higher birth rate which pushes a faster spread of non-belief. However, after re-reading the example a few times, I now think that you are defining the belief itself as the desire for >2 children. Is this correct? If so, then yes, the belief would spread in both total and ratio, hence population increase.

        I am not sure that this aspect is not already considered though. At least, it seems quite doable to include this aspect. There is an inverse relation between birth rate and education. It is hard to expect education to decrease when it is becoming more available. Similar information could also be used to gain an idea of the local/global change in the birth rate, i.e. is it accelerating or decelerating, and do other factors aid in predicting a deceleration of the birth rate?

        I can't speak on whether the demographers are considering said factors, but I do agree that they should, and I have also seen many flawed approaches supported by nothing more than "I passed stats in college!!"
        • Apr 27 2012: I think I see your initial confusion. It seems you get it now.

          Generally I think of these beliefs as having a blatant "god wants you to have more children" message in it, however, ultimately the message does not matter. If the effect of the message results in those two conditions, then this belief will overpopulate the planet. I agree that people with no beliefs in the birth related area could average more and do a better job of overpopulating.

          Demographers have concluded that we are not going to overpopulate the planet. When education, wealth, and women's rights exist, they see that birth rates drop. They take that correlation and conclude there is a mechanism that causes this drop. Their solution for high birth rates is to ensure we all have a good education and wealth and can freely choose how many children we want. (see the two TED talks).

          If I stated that the demographic transition theory is bogus because it is only a correlation, thus nothing ensures we will average less than two, demographers would point me to their pile of data that "proves" we do average less than two when their their variables are present. I won't make a dent in their thinking. This topic's logic shows where their logic is flawed, their extrapolation techniques are bogus, and directs them to change their data collection and data interpretation techniques.

          But, more importantly, I see no way to prove that a belief with these conditions cannot exist. I also see no great way to hunt down all those that have these beliefs and track their growth. If you think about how to prevent these beliefs, I am hoping you and everyone else that comes in contact with it, will conclude that the only way to prevent these beliefs, is with universal understanding that beliefs like that are immoral.

          I need noted experts to state that they agree with that last sentence.

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