Crémieux Profile picture
Sep 5, 2024 13 tweets 5 min read Read on X
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🧵 Image
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. Image
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! Image
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. Image
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. Image
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. Image
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.

Want to learn more? See:
See this too, and note that it depicts rank correlations:
See this as well, on how very diverse data produces the same results:
And finally, see for the source of our current best estimates.sebjenseb.net/p/most-accurat…
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:
Image
Image

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More from @cremieuxrecueil

Apr 2
A new meta-analysis and systematic review on the effects of social media abstinence interventions on mental health has been published.

First result: No effect on positive affect: Image
Second result: No effect on negative affect. Image
Third result: No effect on life satisfaction in general. Image
Read 6 tweets
Apr 2
Happy Autism Awareness Day! I think too many people are 'aware' of autism.

Have you ever met someone who claims to be autistic, but they've never been diagnosed?

Self-reported autism spectrum disorder (ASD) is practically uncorrelated with real, clinician-diagnosed autism🧵 Image
Sort self-reporters into those with high and low ASD scores, and you get the bars on the left. The "high-trait" self-reporters look like people with diagnosed autism (ASD column).

But they're more socially anxious (middle) and avoidant (right). Image
So far, the means of distinguishing diagnosed from self-reported autistics have been crude.

To get a more nuanced understanding of their differences, we have to look at behavior.

For that, we'll start with the social control task.
Read 14 tweets
Apr 1
Ending Credentialism could mark the beginning of an era of American rebirth, with benefits for everyone🧵

For starters, it could mean young people get to enjoy more of their adult lives being adults: Image
Ending credentialism means affirmative action will become less harmful, and you can be more confident that your doctor is qualified rather than someone who replaced a qualified person in the pipeline. Image
Without credentialism, women's ability to select on educational credentials will be impaired, and they'll have to make better judgments.

Men aiming to leverage credentialism in the dating market in their favor will lose that edge, too. But that's good, because it's a lousy edge. Image
Read 9 tweets
Mar 31
I just updated one of my articles a second time.

It has to do with Justice Jackson's comments that when Black newborns are delivered by Black doctors, they're much more likely to survive, justifying racially discriminatory admissions.

We now know the study contained fraud🧵 Image
The original article claimed that, when Black babies are attended to by Black physicians, their infant mortality rates decline substantially relative to when they have a White physician.

Justice Jackson cited this in the Supreme Court, even though it was implausible. Image
A few months back, we learned that the original finding was driven by the authors failing to include a required control variable.

Not only that, but they seemingly knew they this variable was important.

Read 13 tweets
Mar 30
Thread of natural sources of different medications.

We can thank the Gila Monster for modern GLP-1 drugs like Ozempic Image
Image
Ziconotide is a powerful non-opioid painkiller used by people who have severe chronic pain that's resistant to other forms of treatment.

It was discovered in the venom of killer Cone Snails. Image
Image
Trabectedin is a chemotherapy drug that was isolated from an extract of sea squirts. Image
Image
Read 19 tweets
Mar 30
In case it's unclear, I think the mechanism here is likely to be preferentially enlarging productive firms.

In more competitive economies, more productive firms have larger market shares🧵

America is a stand-out example of this: Image
Prior to the fall of the Iron Curtain, markets in Eastern Europe were remarkably inefficient.

After its fall, market reforms occurred, and after they took place, they went from less efficient firms capturing larger market shares to the opposite: more efficient firms dominated! Image
The thesis is this:

America's stock markets are set up in a way that, incidentally, promotes more efficient firms capturing larger market shares.

There's not yet enough data to know if this is true, but time will tell if this possibility holds up.
Read 4 tweets

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