I have also wondered why in some contracts there is a clause relating to the percentage of students that like or don't like a foreign teachers class. Who is in charge? Seems that at many schools the TA's and students have more authourity than the foreign teachers.
So if students ( or a TA ) think an FT's class is boring, or the FT is too strict, they have the right to remove that teacher? What a lot of BS that is!
Much better to work at a public university where you can teach what you want, and how you want without any interference from pests like TA's or a useless DOS.

China only needs FT's who can make their lessons entertaining enough to make students like English.Those of us who are here tonight at our company's Christmas Party are only those who were able to satisfy their students from the outset,and we should continue to do so in order to be able to attend future ones.