It´s multi-faceted tool for learning .
It´s a formal or informal observation of teaching
Trainee teachers who observes teachers.
Teacher trainers who observe trainees teaching.
Teacher developers who observe teachers.
Trainee trainers who observe teachers and trainee teachers.
Observation as a learning tool is quite a recent develpment in tha literature of teacher preparation and education.
Analyze the best way to obtain a better result when applying the teaching method.