Ok, this applies to California specifically, but parts of it ring true for Hong Kong and virtually any educational system.

Firing tenured teachers can be a costly and tortuous task - Los Angeles Times

Reading some of that article gives me a greater appreciation for the teachers in Hong Kong's international schools.

From what we've heard the problems with teachers in HK tend to be related to laziness, cultural difference and in a few cases incompetance. Atleast we don't seem to have to worry about sexual abuse, illegal behavior, drugs and other problems (brought in by the teachers mind you) in Hong Kong.

Classroom ineffectiveness is hard to prove, administrators and principals said. "One of the toughest things to document, ironically, is [teachers'] ability to teach," Wallace, the Daniel Webster principal, said. "It's an amorphous thing."

District officials thought they had a strong case against fourth-grade teacher Shirley Loftis, including complaints and other evidence they said dated back a decade.

According to their allegations before the commission, Loftis, 74, failed to give directions to students, assigned homework that wasn't at the appropriate grade level and provided such inadequate supervision that students pulled down their pants or harmed one another by fighting or throwing things. One child allegedly broke a tooth, another was hit in the head after being pushed off a chair, a third struck by a backpack.

The commission, however, sided with Loftis. It acknowledged that she showed signs of burnout and "would often retreat from student relationship problems rather than confront them."

But it said the district did not try hard enough to help her and suggested administrators find her another job -- perhaps training other teachers. "She's obviously an intelligent lady, and such a program might well succeed."
* Building a case for dismissal is so time-consuming, costly and draining for principals and administrators that many say they don't make the effort except in the most egregious cases. The vast majority of firings stem from blatant misconduct, including sexual abuse, other immoral or illegal behavior, insubordination or repeated violation of rules such as showing up on time.

* Although districts generally press ahead with only the strongest cases, even these get knocked down more than a third of the time by the specially convened review panels, which have the discretion to restore teachers' jobs even when grounds for dismissal are proved.

* Jettisoning a teacher solely because he or she can't teach is rare. In 80% of the dismissals that were upheld, classroom performance was not even a factor.

When teaching is at issue, years of effort -- and thousands of dollars -- sometimes go into rehabilitating the teacher as students suffer. Over the three years before he was fired, one struggling math teacher in Stockton was observed 13 times by school officials, failed three year-end evaluations, was offered a more desirable assignment and joined a mentoring program as most of his ninth-grade students flunked his courses.