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.
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.
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.
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:
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.
On the right, you can see states with policies that give schools more money when their students are diagnosed with autism.
When these policies pass, autism diagnoses increase by almost 25%!
Incentives really do matter for autism diagnoses.
For example, people on SSI receive larger payouts if they're diagnosed with autism.
After the economic downturn in 2008, the most heavily impacted age group started getting diagnosed with autism at an incredible rate:
Similarly, because laws in many places mandate providing more resources to autistic children, parents have sought to get their mentally retarded children diagnosed as autistic.
Using California as an example, more than a quarter of the rise 1992-2005 was due to this:
During Bernie's second set of questions in today's Senate confirmation hearing, @DrJBhattacharya came very close to describing the U.K.'s RECOVERY trial and arguing that the U.S. should emulate that sort of pragmatic clinical trial.
Bernie cut him off, but he shouldn't have🧵
The RECOVERY Trial was the in-patient equivalent to the community-level PRINCIPLE Trial.
Both were trials run in the U.K. to figure out what works for keeping people off of serious treatments like ventilators and out of the morgue after they've been infected with COVID-19.
RECOVERY was an amazing success, but it can't be done in the U.S., because America's healthcare resources are not aligned like they are in the U.K.
In Britain, the NHS and the country's death index (how deaths are tracked) enable people to be easily signed up and tracked.
The Biden administration harassed police and fire departments for asking their recruits to have a bare minimum level of literacy, numeracy, and physical aptitude.
Today, the DOJ has dismissed all of those cases with a clear message:
Competence is legal again.
If you would like to understand the test questions that caused the Biden admin to go after these departments for 'disparate impact' reasons, I've written some threads.
Here are questions for U.S. v. Maryland State Police: