Crémieux Profile picture
Jan 8, 2024 • 10 tweets • 3 min read • Read on X
Achievement gaps do not simply reflect geographic sorting.

This fact has been known for more than a century now, but some people still don't get it.

Shortđź§µ

First: achievement gaps exist within the same schools.Image
This is not just true for race, it is also true for class. Image
When it comes to district-level family incomes by group, we see that intercepts differ.

In other words, even when lower-performing groups are wealthier, they tend to do worse than higher-performing groups. Image
If you're reading this, you probably know that this replicates the results for rearing household income (1/3):
Consider Reardon, Kalogrides & Shores (2019). They found that even in districts where lower-performing groups had higher SES than Whites, they still tended to perform worse.

In this picture, 79% of the mean Black-White gap is independent of SES. At the metro level, 62% was. Image
It is a pernicious myth that test scores and achievement gaps are mere reflections of geography and that geography plays a major causal role in test scores.

The truth is that their association primarily reflects selection.
I neglected to mention this: results from Moving to Opportunity suggest no significant effects on test scores.

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More from @cremieuxrecueil

Nov 3
I'm not taking a stance on whether inflammation drives cancer, but I will say it's very true that GLP-1 drugs reduce inflammation—a lot!

Tirzepatide at any dose greatly reduced levels of high-sensitivity C-reactive protein and interleukin-6, two important inflammation markers: Image
I have actually had people thank me for getting them on this stuff precisely because they had inflammation issues that these drugs *immediately* solved for them.

Here's an example I've posted before: this man's back pain was cured!

Read 4 tweets
Oct 31
The CDC's new Advisory Committee on Immunization Practices (ACIP) didn't put out immunization guidance for 2025-26.

So some researchers got together and did the government's job for them. Here's what they foundđź§µ

First, the RSV vaccine is great for preventing hospitalization! Image
The next thing up is the flu vaccine.

These are still showing a touch lower efficacy than in previous years, but they're still

(1) good
(2) worth it
(3) even more worth it for infants and children Image
Then we have the COVID vaccines, which still seem to be useful enough to save a lot of lives.

These are also still better for the old.

That's good! Image
Read 6 tweets
Oct 27
How rich are American workers?

Very!

After accounting for taxes, transfers, cost of living differences and so on, American workers make far more than their counterparts across the OECD. Image
Is this just because Americans work more?

No. That has something to do with it for some comparisons, but it's not everything.

Americans are also more productive and they get to take home more of what they earn. Image
This is an update on the 2021 numbers I previously presented here: x.com/cremieuxrecuei…, x.com/cremieuxrecuei…, x.com/cremieuxrecuei…

When we have 2024 numbers or later numbers, I'll update to those. But we have to wait on the OECD to release that data, so until then, enjoy!

Here's the old style plots if you want those:Image
Image
Read 4 tweets
Oct 27
Wow!

Across basically all of Europe, people at higher income levels are now *more likely* to become parents!

This is a stunning shift! Image
Among men, this relationship goes a while back now, and in several places, the income gradient has gotten more extreme. Image
Among women, there are some recent crossover events, where the low-income used to be more likely parents than the rich, but now it's different. Image
Read 6 tweets
Oct 26
Wolf packs are remarkably good at respecting each other's established borders. Image
The project this data is from sometimes releases videos of how this plays out.

For example, here's a video of this playing out for a few wolves over a single day in Spring.
Alternatively, about 10-20% of wolf populations lack a pack. They're "lone wolves" and they're more likely to just wander across the territory of different packs

But this isn't permanent! Apparently this one eventually joined a pack and changed his long-distance traveling habit!
Read 6 tweets
Oct 23
Air traffic control has a major problem in the pipeline.

ATCs are underpaid and overworked.

99% of control towers were understaffed in 2023 and the number of communication mishaps and near-misses between commercial aircraft skyrocketed.

I think the solution might be dronesđź§µ Image
You might think: Wait, haven't drones been smashing into planes recently? How are they going to help?

That's true! I've attached some pictures of drone-related damage. It's real and getting worse, I'll give you that.

The answer lies in drone communication.Image
Image
Image
Image
Drones don't yet, but they can start to, constitute a low-level communication and monitoring layer around airports and other protected airspace.

Drones can relay information about the locations of other drones, obstacles, incoming planes, and so on. Image
Read 16 tweets

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