I just read this article: https://medicalxpress.com/news/2018-06-iq-scores-1970s.html
It references a study that seems to indicate the average IQ is dropping. On the surface this sound like a bad thing, but is it really?
I have not read the study myself, so this is really more about the math behind IQ scores to highlight how things are not always as they seem. It is likely, even probable that the study to all of this into account, but as the article in question did not address this, one cannot know without investigating for themselves and to assume the study is without it's flaws is a really bad idea. Just look at the study that is constantly cited to show that vaccines cause aspergers. The author of that study has admitted to faking the data. Moving on...
First, we need to understand what an IQ score tells us. A score of 100 means that you achieved a median score. Median is not the same as average. If 100 people take the same test and 49% get all the answers right and the other 51% get 0 answers right, the median score is 0. If this were an IQ test, that would mean the lowest 51% of the population had an IQ score of 100 with everyone else getting a score above 100 making the average IQ something above 100.
Now, let's flip that on it's head. This time, 51% of the test takers get every question right, and 49% get every question wrong. In this case, the median score is 100% giving the top 51% of the population an IQ score of 100 and the lower 49% would have an IQ score that is some value below 100 with the lowest possible value being 0. In the worst case scenario the lowest average IQ in this case would be just shy 50.
Because the IQ scale is not fixed, but rather is a moving target based on the median score, you cannot assume that when the average goes down that it implies people are getting dumber as it could just as well indicate that people are on average getting smarter. My example, while extreme, demonstrates this perfectly. In it, 2% of the population got smarter resulting in the average score going from over 100 to below 50. So congratulations to everyone on the lowering of the average IQ! We might just avoid Idiocracy yet. I'm sure the management of Fudruckers will be pleased!