Crémieux Profile picture
Sep 16, 2024 14 tweets 4 min read Read on X
I have a pretty major update for one of my articles.

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

We now know she was wrong🧵 Image
So if you don't recall, here's how Justice Jackson described the original study's findings.

She was wrong to describe it this way, because she mixed up percentage points with percentages, and she's referring to the uncontrolled rather than the fully-controlled effect. Image
After I saw her mention this, I looked into the study and found that its results all seemed to have p-values between 0.10 and 0.01.

Or in other words, the study was p-hacked. Image
If you look across all of the paper's models, you see that all the results are borderline significant at best, and usually just-nonsignificant, which is a sign of methodological tomfoolery and results that are likely fragile.

With all that said, I recommended ignoring the paper. Image
Today, a reanalysis has come out, and it doesn't tell us why the coefficients are all at best marginally significant, but instead, why they're all in the same direction.

The reason has to do with baby birthweights.
So, first thing:

(A) At very low birthweights, babies have higher mortality rates, and they're similar across baby races;

(B) At very low birthweights, babies have higher mortality rates, and they're similar across physician races. Image
Second thing: Black infants tend to have lower birthweights.

MIxed infants tend to birthweights in-between Blacks and Whites, and there's a mother effect, such that Black mothers have smaller mixed babies than White mothers (selection is still possible)

Third thing:

(A) Black babies with high birthweights disproportionately go to Black doctors;

(B) The Black babies sent to White doctors disproportionately have very low birthweights. Image
If you control for birthweight when running the original authors' models, two things happen.

For one, they fit a lot better.

For two, the apparently beneficial effect of patient-doctor racial concordance for Black babies disappears:Image
At this point, we have to ask ourselves why the original study didn't control for birthweight. One sentence in the original paper suggests the authors knew it was a potential issue, but they still failed to control for it.Image
PNAS also played an important role in keeping the public misinformed because they didn't mandate that the paper include its specification, so no one could see if birthweight was controlled. If we had known the full model details, surely someone would have called this out earlier.
Ultimately, we have ourselves yet another case of PNAS publishing highly popular rubbish and it taking far too long to get it corrected.

Let me preregister something else:

The original paper will continue to be cited more than the correction with the birthweight control.
The public will continue to be misled by the original, bad result. PNAS should probably retract it for the good of the public, but if I had to bet, they won't.

So people like Justice Jackson will continue to cite it to support their case for racial discrimination.
They'll continue doing that even though they're wrong.

To learn more and to find the article linked, check out my post on this: cremieux.xyz/p/missing-fixe…

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More from @cremieuxrecueil

Jun 4
The Wall Street Journal just published the FDA's Opinion piece-length rationale for banning talc.

I was happy to see they were citing studies, but after I read the studies, I was dismayed:

The FDA fell victim to bad science, and they might ban talcum powder because of it!

🧵 Image
The evidence cited in the article is

- A 2019 meta-analysis
- A review by the International Agency for Research on Cancer (IARC)
- A 2019 cohort study from Taiwan

Let's go through each of these and see if the FDA's evidence holds water. Image
The first piece of evidence they cite is a meta-analysis, and it's a doozy.

The study includes 27 estimates of the observational association between talc use and ovarian cancer rates.

Three estimates come from cohort studies. Those are fine. The problem is the 24 other studies.
Read 42 tweets
Jun 3
Let's make this even clearer.

The severity of COVID vaccine-related myocarditis was far lower than the severity of COVID-related myocarditis, which instead looked like regular viral myocarditis.

You can see this in many cohorts. For example, this was seen in France: Image
This result replicates everywhere it's tested.

We knew this from the initial small studies... Image
Image
And we knew this based on somewhat larger Scandinavian register-based work as well

Do note, however, that the Scandinavian work had a poor case definition for infection-driven myocarditis compared to other cohorts. As the long-term study linked in the QT shows, they missed most Image
Read 22 tweets
Jun 2
A friend of mine won a bet about myocarditis and the COVID vaccines a few years ago.

He bet that the myocarditis side effect was real and sizable for young men.

While COVID was more likely to cause myocarditis in general, among the young, the Moderna vaccine was a bit worse. Image
This still wasn't really something to worry about.

Look at the rates. They're incredibly small, at just about 15 per 1,000,000 under 40 years of age for the second dose of the Moderna vaccine and 3 per 1,000,000 for the Pfizer one.

Compare to whole-population COVID-myocarditis.
The vaccines were safe and effective, but this side effect was not all hype, as some health authorities jumped to claim.

Oh well, lessons learned. Hopefully.

Worth noting, though, that the vaccines still saved more lives than were harmed. ~15-20m lives by late 2022, in fact. Image
Read 4 tweets
Jun 2
With so many people identifying themselves as having disorders that they're not diagnosed with, the U.K. will certainly have a glut of diagnoses in the near future.

People think it, and then make it so, and if the state honors those diagnoses, they'll end up paying out the nose. Image
Similarly, in Minnesota, the state recognizes clearly fraudulent autism diagnoses.

Who's doing them? Normal parents, but also certain communities.

For example, Somali immigrants have figured out how to get more welfare funds by getting their kids fake diagnoses. Image
As a result, fraud cases have opened up and the FBI has begun to investigate the Somali communities where autism funds are getting disproportionately directed.

In 2009, Minnesota Somalis had an autism rate about 7x the non-Somali average. Today, it's still high, at just over 3x.
Read 6 tweets
Jun 2
Obesity has immense costs, and not just direct, medical ones.

Obesity makes people miss work and increases the odds they're on disability. It also increases presenteeism and workers' compensation costs.

The total cost is in the hundred of billions to over a trillion per year. Image
The costs of overweight and obesity are so extreme that making reducing the obesity rate can pay for itself if it can be done at prices achievable today.

And this number doesn't even consider all the costs. There are high costs from cardiovascular issues and cancer, too. Image
The most extreme estimate I'm aware of put the cost of obesity in 2016 at $1.7 trillion per year, due to $1.2 trillion in indirect costs.

But this study calculated costs based on all treated comorbidities associated with obesity/overweight, so might've been skewed.Image
Read 5 tweets
May 30
Does testosterone make people have more masculine economic preferences?

Does it make people act more like Republicans?

We now have a large, pre-registered double-blind randomized controlled study that provides an answer🧵 Image
To test whether testosterone masculinized economic preferences, the first thing to do was modify testosterone levels.

This was done with an intranasal administration that boosted female levels by about 82%, and male levels by a bit over 100 ng/dl.

Not huge, but sizable enough. Image
The next thing to do was test!

This was done three times over in games that assess economic preferences.

The first of these was the ultimatum game, within which, men tend to be more aggressive in their offers. Image
Read 13 tweets

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