Success can be measured either by external or internal indicators of performance. Ideally, both are incorporated.
Examples of external measures include achievement of coaching goals established at the outset of the coaching, obtaining a promotion, performance feedback that is obtained from direct reports, colleagues, the manager, personal and/or business performance data (e.g., productivity, efficiency measures). The external measures selected should be things the individual is already measuring and has some ability to directly influence.
Examples of internal measures include self-validating assessments that can be administered during the coaching process, changes in the individual’s self-awareness and awareness of others, shifts in thinking that create more effective actions, and shifts in one’s emotional state that inspire confidence.