Over the past few years I have met many student-teachers from various programs across the Philadelphia area and have yet to find one that provides as much trial and error as mine. In fact, under Chapter 354.25 of the PA Code, "the preparation program shall be designed to provide a minimum 12 week full-time student teaching experience." And with just 3 months of time in a classroom (not all of which involves running the class) a student-teacher can become a full-time teacher. At the end of my 9 months in a school (7 of which were spent running at least one class) I still was not completely prepared for what lay ahead.
In the report that came out in September 2011 entitled, Our Future, Our Teachers, Arne Duncan and the US Department of Education want to change the way teacher preparation programs work so that they create effective and knowledgeable educators for our children. Over and over it emphasizes "clinical experience" that is necessary to become a good teacher, yet the recommendations made include tracking systems to identify these teachers and use these data to reflect back on their schools.
Instead of focusing so much on the punitive measures that seem to be come from the Department of Education, I would rather push for new teachers to get more experience sooner and not be let off the hook once finished. Teacher mentors are useful people who can support people in their first five years of the job. Thinking and acting positively like that will truly make a difference.