Concerning the question of why people leave teaching:
I spend a lot of time in schools, and my son is a teacher. I'm glad Mary Hannigan wrote on this subject. I've been trying to, for some days now, but I have not been able to compose a suitably-short response. As WORKPLACES, most schools are ghastly! Mary is correct when she says that teachers are typically treated as VERY low-level employees, are expected to carry out truly difficult tasks in settings where one cannot possibly succeed, when anything goes wrong the teacher is blamed (although the situation may have made success impossible), there is no true agreement on the underlying nature of their tasks, and students are often required to attempt things that make no sense.
I'll try to give 2 examples briefly:
1) In an elementary school I know, there is a 6th grade boy who reads far below grade level, and who is largely unable to get along with other students. The school has a 2-hour science period (and longer periods CAN be helpful for more thoughtful learning) - but in this case, this boy is pulled out of the FIRST hour of the science period for remedial reading help. As a result, in every science period he returns to class in the middle of this 2-hr. period. So what does he face? Everybody else in the room has been thinking about today's task for at least an hour more than he has. He cannot READ to try to catch up. He cannot LOOK TO OTHER STUDENTS for help, because he cannot get along with the other students.
So he - perhaps the most needy kid in the class - must try to do 2 hrs. work in 1 hour, must learn from reading (which he cannot do), must learn from other students (impossible), must therefore face impossible frustration, and must contain this frustration (although this is the kind of thing he is most unable to do).
How would you feel, as this boy's teacher, if you knew this was an inappropriate treatment, but were told (condescendingly) that this is the way it HAS to be?
2) In a large high school I know, all classrooms are kept locked, as are also the men's rooms. Substitute teachers are NOT given keys. What does it do to the status of these teachers, in the eyes of students, when they must wait in the corridor for someone who HAS a key to let them in to the room where they are supposed to teach? (Not to mention the question of how to go to the men's room...)
A few years ago, when concern for math/science instruction in US schools was getting a lot of attention, Education Weekly came out with a special issue devoted entirely to this subject - entirely, that is, except for one report that argued that no improvement was possible as long as working conditions for teachers continued to be the way they were. Any good math or science teacher can qualify for other jobs that offer much more respect, comfort, and effectiveness in the workplace - and that will probably also pay more money!
The question is: why does anyone STAY in teaching?