Writing Behavioural Objectives
An objective is a statement of what the students should be able to do once they have completed a section of the course. It is an indicator of what learning has taken place. Notice that I said indicator rather than measure. Learning goes on inside a student's head and, therefore, cannot be directly measured.
So while it is perfectly possible to have an objective of 'understanding interpersonal skills', this is not very useful for measuring the effectiveness of the training. The students could be asked whether they understand interpersonal skills, and the trainer could gain a 'feeling' for how much has been understood by general questioning or observation. But still, there would always be doubt as to whether the students had met the objective.