Great teachers are not born, they're made. It takes time to become a great teacher.
We are more than just the sum of our teacher evaluation (IMPACT) scores. But let's face it, IMPACT scores determine whether teachers remain in our school system or get fired. I've seen great teachers get forced out of DC Public Schools because they didn't really have a good grasp of the Teach standards by which teachers are judged. Not to mention the training that has been provided in recent years by DCPS has been less than adequate.
It seems like a 'no-brainer' to me that professional development is one of the main ingredients to turning around teachers' effectiveness. Not just any professional development but specific training on the Teaching and Learning Framework (TLF), Common Core state standards and job-embedded professional development.