With any type of one-to-one intervention, there is a tendency to want impressive improvements, outcomes and results. When the assignment is part of a formal program, the organization may especially want to evaluate results from the mentoring activity along criteria such as increased promotion rate of mentees, less talent lost to competitors, etc. What is ultimately beneficial to the learning and progress of a mentee may not reveal itself, whether within the timeframe of an assignment, in the conscious mind of a mentee, or as something directly linked to the mentoring sessions.
Just because an impact or outcome of a mentoring assignment is less obvious or delayed does not mean that it is insignificant or less important; it simply means you are less aware of them. The principle that some results can be measured and some can’t is intended to strengthen your approach rather than dilute it. You can stay committed to supporting your mentee to make progress and trust that you are doing that, even when you are sometimes unable to identify exactly how that progress is happening
When you develop consistency with the above, all that is left to do is trust that you will make a positive difference to whomever you support as a mentor. Sometimes they will show up unexpectedly to surprise and delight you.