Schools don't fire incompetent teachers because they don't have competent teachers to replace them with

It's a myth that schools want to fire incompetent teachers.

Who would replace them?

Or maybe the problem is that administrators are too lazy to document incompetency. Or could it be that principals just don't know who to start with? There's quite a bit of incompetency going around, and not just in the teaching profession.

Susan Ohanian notes that "...the main targets of firing and harrassment are the outspoken teachers who want to change the system, or who criticize the boss, NOT the lazy, incompetent teachers, who are portrayed as the chief beneficiaries of tenure."*

Susan is right.

Administrators (and teachers) who are unsure of their own abilities often react with hostility and aggression when a colleague starts talking about how things could be improved.

*http://www.susanohanian.org/show_atrocities.html?id=7368