How to measure the effectiveness of a coaching is a tough question as how do you measure a behaviour change? Coaching is deeply personal for the coachee and the work starts when we explore where the client is stuck. The coaching relationship and the work between client and coach offers the coachee many insights into how they see themselves. This enables us to start with what mindset the coachee is in now and where they would like to get to next. Once the mindset objective is clear, it's the work on behaviours that really gets noticeable results as this is a place where others visibly see a shift and can support the process with feedback and encouragement.
When a client starts to identify how they would like to behave when "unstuck" it releases them into an experimental phase where they can find more opportunities for trying new behaviours that overwrite the old ones. Neuroscience studies tell us by repeating our new found behaviours we can create new neural pathways in our brains. We now associate this with how we form new habits. Not all experiments will go perfectly, but every new insight from trying something new can deliver more learning and offer life changing momentum away from the stuckness. That has to be worth more for our well-being than a monetary figure on behaviour change.