The article didn't link data so I can't dig in further.
https://personalityanalysistest.com/iq-score/what-is-the-sta...
IQ tests measure relative to a reference population. So we can speak of the IQ of a person aged 20 born in 1990 on a test where 100 is the average score at age 20 of the population of those born in 1960, etcetera.
Changes in average IQ has been something that has been spoken of in the literature since Flynn was young, back when IQ scores were rising.
So now we need to be really careful about bias in the sample groups.
To say IQ scores are dropping and we don't know why then means to me we don't know what variables were the key drivers of the first groups results so we therefore cannot possibly create a consistent second group to measure against the baseline.
I'm still stuck but I'm often dense and skeptical on these type of analysis.
This is why there are practices around statistics sampling and confidence intervals and whatnot. Of course we can’t exactly recreate, that’s impossible, but we can create samples in a way that the results are generalizable in both the baseline and the comparison. And the results are useful.
I have a friend who says that it’s impossible to know if we can’t sample 100% (“how can we know how it will work in 100 million if we only test in 1000?”) and it’s frustrating how just basic concepts of math and statistics make it hard for them to accept any research.
Another source is the number of clinical cases of mild mental retardation. This will mostly depend on how large the population subgroups with lowest IQ are, but if they are approximately fixed and there's no explosion in assortative mating it would be possible to calculate the true mean from that.
This assumes both classification criteria and testing rates remain constant over time. Both are poor assumptions.
It’s easy to see how such a system can be used to measure a decrease or increase of height over time, even though your normalizing your reporting and even though the markings are irregular.
So many variables here including way the math portion was measured moving to multiple choice in the 1990s when the scores start dropping, hopping on a flight, still skeptical.
Other quick one, all 95% confidence interval on data that moves less than +/- 2.5% either way. I understand confidence interval isn't a straight linear margin of error, it one I'd want to also look at further.
> But more research is needed to better understand other environmental factors thought to be linked to intelligence. Robin Morris, a professor of psychology at Kings College in London who was not involved in Ritchie’s research, suggests that traditional measures of intelligence, such as the IQ test, might be outmoded in today’s fast-paced world of constant technological change.
> “In my view, we need to recognize that as time changes and people are exposed to different intellectual experiences, such as changes in the use of technology, for example social media, the way intelligence is expressed also changes. Educational methods need to adapt to such changes,” Morris said.
If you start digging around to see that you're fairly comparing the groups then you'll almost always be able to split hairs. Most statistics outside of a theoretical context are flawed if you poke them hard enough.