reform organization study criticizes professional development

The authors of the study argue:
"We found no evidence that any particular kind or amount of professional development consistently helps teachers improve."
"School systems are failing to help teachers understand how to improve—or even that they have room to improve at all."
"But school systems shouldn’t give up on teacher development. And they shouldn’t cut spending on it, either. Rather, we believe it’s time for a new conversation about teacher improvement—one that asks fundamentally different questions about what great teaching means and how to achieve it."

"n short, we bombard teachers with help, but most of it is not helpful—to teachers as professionals or to schools seeking better instruction."

The study is available here:
http://tntp.org/publications/view/evaluation-and-development/the-mirage-confronting-the-truth-about-our-quest-for-teacher-development

Here's a Slate magazine article discussing the study:
http://www.slate.com/blogs/schooled/2015/08/06/professional_development_for_teachers_new_study_questions_value_of_teacher.html

Please read the study and share what you think? What makes a professional development program worth your time and energy?
edited by Clay Dube on 8/6/2015