Well, this is an odd little piece of research.

The National Center for Research on Education Access and Choice (REACH), aka Doug Harris, the guy who brought us all that research saying that all-charter New Orleans was hunky dory, has produced a new report looking at how charter schools affect the supply of teachers from university-based education programs. 

Short version: in cities, when you get more charter schools, you get fewer teachers coming out of college and university teacher prep programs. Harris finds that elementary, math, and special ed suffer the most.

This would be an excellent time to remember that correlation is not causation (here's the awesome spurious correlations website to remind us that, among other things, cheese consumption rises with the number of people killed by being tangled in bedsheets, and swimming pool drownings rise and fall with Nicolas Cage film appearances). 

So charter schools and the teacher pipeline might very well have absolutely nothing to do with each other. We need to be clear on that right up front.

But if they are connected, what could explain that?

Harris and his co-author Mary Penn don't have an explanation for the connection, which they first noticed while doing their New Orleans research. 

The National Alliance for Public [sic] Charter Schools offered a rebuttal. Part of it was just a silly tautism-- there are fewer teachers coming out of traditional programs because there are fewer persons entering programs. And then this:

Although charter schools are a convenient scapegoat for the report author, they are simply not the cause of the nation’s teacher shortage. Given the dire labor shortage, we as a nation need to be open to alternative certification and preparatory programs that attract talent from untraditional sources and provide teachers for the classrooms that desperately need them. Charter schools seem to understand that point.

Especially cranky words from a group that actually sits on the REACH advisory board. 

So what could the connection be? NAP[S]CS hints at it as they profess their love for teachers from "alternative" routes. Charter businesses like teachers without traditional training, and they like temps with a high turnover (like Teach for America). Alternative path teachers tend to leave sooner, which suits charter businesses just fine. And that can have consequences.

No profession recruits its own members quite like teaching. Prospective teachers get to watch the profession for thirteen years. They have all that time to watch and think, "Wow, that looks awesome" or "May God forbid I ever wind up in that job." 

So what might the effect be of watching a steady parade of mediocre beginners who never stick around to become mature professionals? Particularly in a charter where the teacher's job is to simply implement the program they're handed. Just how fun does reading a canned curriculum look? 

I also wonder--charter heavy urban areas tend to be cities where the public system has been beaten down to help sell the charter system, so that teachers in public schools are also laboring harder, in an atmosphere larded with too much disrespect and non-support. None of which makes the profession look particularly attractive. 

As I warned, those two trends (charters up, teachers down) could be the result of some other factor entirely, like Nicolas Cage movies, but it's not that hard to imagine what a plausible link might be. Charters are the point of the spear in a general move to devalue the teaching profession, and a lack of interest in that profession would certainly be a predictable result.