Crémieux Profile picture
Oct 4, 2024 • 10 tweets • 4 min read • Read on X
There are people who desperately want this to be untrue🧵

One example of this came up earlier this year, when a "Professor of Public Policy and Governance" accused other people of being ignorant about SAT scores because, he alleged, high schools predicted college grades better.Image
The thread in question was, ironically, full of irrelevant points that seemed intended to mislead, accompanied by very obvious statistical errors.

For example, one post in it received a Community Note for conditioning on a collider. Image
But let's ignore the obvious things. I want to focus on this one: the idea that high schools explain more of student achievement than SATs

The evidence for this? The increase in R^2 going from a model without to a model with high school fixed effects

This interpretation is bad. Image
The R^2 of the overall model did not increase because high schools are more important determinants of student achievement. This result cannot be interpreted to mean that your zip code is more important than your gumption and effort in school.

If we open the report, we see this:Image
Students from elite high schools and from disadvantaged ones receive similar results when it comes to SATs predicting achievement. If high schools really explained a lot, this wouldn't be the case.

What we're seeing is a case where R^2 was misinterpreted.
The reason the model R^2 blew up was because there's a fixed effect for every high school mentioned in this national-level dataset

That means that all the little differences between high schools are controlled—a lot of variation!—so the model is overfit, explaining the high R^2
This professor should've known better for many reasons.

For example, we know there's more variation between classrooms than between school districts when it comes to student achievement.

As another example, we know that achievement gaps exist along the whole continuum of school and district quality.

If the issue was really zip codes, high schools, and so on, this shouldn't be the case.

The other thing this professor should've known is that high school is biased! GPAs are biased too!

The bias in GPAs has actually been exploited: elite high schools inflate grades and don't report class ranks, so students appear better than they are. Image
But you know what isn't a biased tool for admissions? Just one thing: test scores.

Want to learn more? Here are some sources:

x.com/cremieuxrecuei…

cremieux.xyz/p/what-happens…

cremieux.xyz/p/bias-in-admi…

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More from @cremieuxrecueil

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
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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
Mar 22
WHAT IF

@nyuniversity didn't engage in blatant racial discrimination when they were selecting the Class of 2028? The result would be

- Much higher average SAT scores
- Minimal racial differences
- Very different student demographics Image
Instead, the NYU we get is far more "diverse" than it has any right to be, because the admissions officers had their fingers on the scale.

We know what unbiased admissions would look like, and it's not this.

They're going to fall back on excuses, but nothing will work.
Their defenders might argue Asians do fewer or worse extracurriculars. The opposite is true.

Their defenders may argue Asians have worse personalities. They don't gather that data and it would be biased. Next?

They could argue Asians do less in athletics. OK, but small effect.
Read 7 tweets
Mar 22
Even when men and women are matched for the amount of muscle they have, men tend to be far stronger.

The case against sex-segregating sporting is the case for women only making appearances in sports with relatively equal performance, like archery. Image
This is true for the lower body too. Image
Elite female athletes even tend to be weaker than typical men.

The case against sex-segregated sporting is very clearly the case for eliminating women's participation in sport. Image
Read 5 tweets
Mar 22
We now know NYU violated the law by engaging in racial discrimination in their latest admissions cohort.

They should be punished severely.

In the meantime, NYU should also try to make amends by contacting all overlooked students and sending them admissions offers right now.Image
Image
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This data comes from today's hack of NYU's admissions department and website.

You can see an archive of what their website looked like an hour ago here: web.archive.org/web/2025032213…
Now, as a reminder, Trump has stated that his preferred punishment for universities that continue to engage in illegal racial discrimination is...

Confiscating their endowments, taking away their accreditation, and imposing severe damages on those responsible.

Godspeed. Image
Read 4 tweets

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