I like thinking of observation feedback withing the four buckets.  Diognostic, Prescriptive, Descriptive and Micro-Feedback.  Often times we give prescriptive feedback to new teachers when they really should be give prescriptive feedback.  Also, I really appreciated the video on Feedback.  Thinking about it from the student perspective and communicatin the purpose through that lense will no doubt be more impactful then taking it from the sole perspective of " I want you to be a better teacher".  Although the goal is the same, improve student learning outcomes, the message is quite different.