Almost every mentoring programme reports activity, because activity is what a calendar produces for free. Sessions held is a real number and an easy one, and it says nothing about whether the mentoring worked.
Outcome tracking needs two things activity tracking does not: a goal recorded at the start, specific enough to be judged, and a check-in after the engagement is over. The second is where most tracking stops — and where the outcome usually happens, since promotions, offers and launches land months after the last session.
The useful unit is the milestone, not the session. A goal broken into milestones with a rated check-in after each session produces a curve readable at any point, rather than a verdict available only at the end.
Mentor10
Mentor10 tracks goals as milestones with a rated check-in after each session, and schedules follow-up check-ins after an engagement closes — so the result is captured where it actually occurs rather than where the invoicing stops.