It never ceases to amaze me either that people (parents included) seem fine with the fact that their children are not learning much!
I have seen the correlation first hand between teacher knowledge and student success (or lack there of, whichever may be the case). As I go through the school year, it is really easy to see which topics the students' previous teachers knew well and understood more than the grade level expectations and which were not really understood. It then takes quite a while to "un-teach" the mistakes that they were taught previously.
Every time I've changed schools, whether internationally or in the US, because I teach physics and there are so few true physics teachers out there (as opposed to chemistry teachers or math teachers teaching physics) it usually takes a couple of years before there is a noticeable difference in the students' understanding of physics.
Now, as a parent, it makes me angry too when DD's teachers don't know enough to keep up with her in some cases. I mean, she is still only 7!
My son was just telling me today (on the long drive home) that he appreciates that his teachers have expertise in their subjects and are willing to answer any question even outside the planned lessons.
Almost all, if not all, have some level degree specific to their subject. They may or may not have an additional teaching degree, which is not a requirement at private schools. Several teachers have had successful careers as business owners, engineers, product inventor, and dentist. A few have PhDs. Some teachers were born and educated in other countries. Some American born, have lived in other countries. They are like college instructors.
