Why does the stability of Racket matter? Isn't the real question more about how easy it is to reuse, readopt, reshare, find, etc. materials? I'll point out that the CSEngageEdu site doesn't have a Racket section. If you want me to find 100 programming problems in Python, I can do so immediately (because I published more than that, and I know others who have published even more). It's a simple fact that there's more community and infrastructure around Racket. There's been some interesting arguments that we shouldn't let that stop us - what about the future? But the reality is that right now, it's harder to teach in Racket, and I don't see any compelling evidence to prop it up further.
> Is there any data about how well the students do following each language choice?
I'm sorry, I had to laugh out loud. You've asked a really reasonable question, but it's one that the CS Ed community bickers about endlessly. I wrote a paper for SIGCSE about trends in what we talk about on the SIGCSE Mailing list. Seriously, every few years we get into the argument. Actual data seems to suggest very little. Heck, it's so hard to compare with all the confounding factors and individualized components that it's probably not really meaningful to get a simple answer. Ultimately? It probably doesn't matter. If you can teach 90% of my students with Racket the way I teach 90% of my students with Python, and you have the time and energy, then that's probably fine. But the simple reality where I'm at is that that's not the case - students who were taking Racket here before I arrived were being traumatized (and I suspect it's true at more places than the Racket folks want to acknowledge). If they don't want Racket, and I can teach a good CS1 in Python or Java or JavaScript, why should I fight that? Language choice doesn't really influence pedagogy as much as we might want to think it does, per this quote from the beautiful Meta paper that came out earlier this year:
> “Given the perennial question of which language, if any, is best suited for the teaching of introductory programming, many papers describe empirical comparisons between languages, often finding no significant difference in learning outcomes, but sometimes finding differences in student satisfaction.”
> “The choice of programming language is clearly a highly subjective one and is driven by many competing factors. It is clear that the literature will continue to host publications making the case for different programming language choices — and that no paper or series of papers will ever put an end to the debate, as no programming language will ever satisfy all of the conflicting requirements of an introductory programming course.”