How bad are Richard Lynn's 2002 national IQ estimates?
They correlate at r = 0.93 with our current best estimates.
It turns out that they're really not bad, and they don't provide evidence of systematic bias on his part🧵
In this data, Lynn overestimated national IQs relative to the current best estimates by an average of 0.97 points.
The biggest overestimation took place in Latin America, where IQs were overestimated by an average of 4.2 points. Sub-Saharan Africa was underestimated by 1.89 pts.
Bias?
If you look at the plot again, you'll see that I used Lynn's infamously geographically imputed estimates.
That's true! I wanted completeness. What do the non-imputed estimates look like? Similar, but Africa does worse. Lynn's imputation helped Sub-Saharan Africa!
If Lynn was biased, then his bias had minimal effect, and his much-disdained imputation resulted in underperforming Sub-Saharan Africa doing a bit better. Asia also got a boost from imputation.
The evidence that Lynn was systematically biased in favor of Europeans? Not here.
Fast forward to 2012 and Lynn had new estimates that are vastly more consistent with modern ones. In fact, they correlate at 0.96 with 2024's best estimates.
With geographic imputation, the 2012 data minimally underestimates Sub-Saharan Africa and once again, whatever bias there is, is larger with respect to Latin America, overestimating it.
But across all regions, there's just very little average misestimation.
Undo the imputation and, once again... we see that Lynn's preferred methods improved the standing of Sub-Saharan Africans.
There's really just nothing here. Aggregately, Lynn overestimated national IQs by 0.41 points without imputation and 0.51 with. Not much to worry about.
The plain fact is that whatever bias Lynn might have had didn't impact his results much. Rank orders and exact estimates are highly stable across sources and time.
It also might need to be noted: these numbers can theoretically change over time, even if they don't tend to, so this potential evidence for meager bias on Lynn's part in sample selection and against in methods might be due to changes over time in population IQs or data quality.
It might be worth looking into that more, but the possibility of bias is incredibly meager and limited either way, so putting in that effort couldn't reveal much of anything regardless of the direction of any possible revealed bias in the estimates (not to imply bias in estimates means personal biases were responsible, to be clear).
Some people messaged me to say they had issues with interpreting the charts because of problems distinguishing shaded-over colors.
If that sounds like you, don't worry, because here are versions with different layering:
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I have just put out an article dealing with numerous misconceptions about this topic, and a complete explanation of why autism diagnoses have become more common.
It starts with acknowledging that more kids are diagnosed than in the past:
But this is misleading for a few reasons.
One has to do with how this data was sourced. We didn't have a DSM with autism in it before 1980, so all the oldest people in this cohort were diagnosed as adults.
Adults are underdiagnosed. Go out of your way to diagnose? Same rates.
So something is off about this graph.
A major issue is that the older diagnoses here were done under a more arbitrary criteria: Autism has only been a described thing since Kanner's studies in 1943 and mass diagnosis kicked off in 1980.
In 2016, researchers found that the minority-White wage gap was overestimated by about 10% because, at work, non-Whites tended to partake in more leisure, waiting around, etc.
They delayed releasing the study out of fear Trump would "use it as a propaganda piece."
They explicitly admitted that they let their personal politics get in the way of releasing a study with contentious but correct findings.
That doesn't inspire trust, but at the same time, given the topic, it might!
This isn't the worst example of scientists hurting the public for political reasons.
More infamously, this guy stopped the release of the COVID vaccines to prevent Trump from winning re-election in 2020, killing tens of thousands in the process.
If you want to "fix" this situation within reason, you need to cut funding.
Doing that has disproportionately negative impacts for the educations of people from socioeconomically worse off backgrounds. Or in other words, it hurts upward educational mobility for the poor.
Or, you could provide this presidential administration with a gift:
Centralize the universities and have the government more directly control all the funding. Make them "free".
This is far more likely than alternatives like 'Just give universities infinite money', but still bad
Compared to twenty years ago, kids are eating some types of ultraprocessed foods more and some types less🧵
For example, one thing there's proportionally less of is sugar-sweetened beverage consumption. Meanwhile, there's relatively greater sweet snack consumption.
Overall, the ultraprocessed food (UPF) consumption share is up across young ages to similar degrees.
The increase is definitely there, but it isn't dramatic. For example, going from 61% to 67.5% is an 11% increase in twenty years.
The increase in consumption is not differentiated by the sex of children.
In other words, boys and girls are both eating a bit more ultraprocessed food.