This is a question I ask myself occasionally. But being qualified to teach CS is a somewhat tricky question. In my state, there’s no certification for CS. I can get certified in business and information technology, but I’m not sure what that entails. The web site is a bit Byzantine. In states where there is CS certification, it’s pretty straightforward. You need a bachelor’s in CS plus the education program, standard for any other field. I have neither of those things (and my job requires neither). I have about 20 years of teaching experience. I have taken several classes in pedagogy. I have about 10 years of IT experience and about two years of programming experience (at least in the language I teach). It sounds okay, but it often feels like not enough.
I certainly wish I had the breadth of knowledge in the field a CS degree would give me. If I had the CS degree, though, I don’t think I’d teach. I think I’d be working in industry. The money’s certainly better. And this is the argument made by many about why there aren’t more CS grads teaching CS at the K-12 level. There’s a push by some organizations like the CSTA to increase CS certifications and have more teachers with the “right” credentials teaching CS. I don’t disagree with this idea. But first you need the demand for those teachers, which isn’t there right now. CS isn’t a core academic subject so it’s not taught everywhere, and even where it is taught, there are not enough courses for a full time CS teacher.
So at many places, the lack of certification standards benefits both the school and the teachers. The school makes do with a math teacher who can program or has the tech person teach a couple of courses. And the teacher hones their CS skills in other ways, through online or summer courses or just through reading and practice. Is it ideal? Probably not. But it’s what’s in practice at many places.
There’s a bigger question about credentialing in general that my own anxiety raises. Does having a degree in x qualify you to teach x? Does not having the degree disqualify you? Are there different routes one can take to be qualified? For example, could a well-read author teach not just writing, but also literature? And what about education research and training? Is that more important than experience? Is being qualified to do anything really that cut and dried?