When Anna, the chief financial officer of a global manufacturing firm, completed a six-month coaching programme at INSEAD Executive Coaching (IEC), her CEO asked her a simple question: “So, what did we get out of it?”

Anna was stumped. She felt different, more confident in delegating, calmer under pressure and more attuned to her team’s unspoken concerns. Her colleagues had noticed, too. But none of this could be plotted neatly on a spreadsheet. 

She’d been wondering herself: How do you measure insight? How do you quantify a better night’s sleep because you’ve stopped catastrophising before a board meeting? And how do you track progress when every month of coaching brings fresh shifts and new behaviours?

This is the paradox at the heart of executive coaching. Everyone who has gone through it agrees it matters. Everyone senses its impact. Yet, pinning down that impact in a way that satisfies both coachees and the organisations they work for is one of the toughest challenges in leadership development.

The ROI mirage

Executives are addicted to numbers. So, when it comes to coaching, the reflex is the same: Show me the numbers.

The most popular approach is 360-degree feedback: before-and-after snapshots of how peers, bosses and subordinates perceive the leader. Competency frameworks, engagement surveys and performance metrics play starring roles. Did the leader become more empathetic? More decisive? More “visionary”? Some firms even attempt the holy grail: a coaching return on investment. How much productivity or profit can be attributed to a series of confidential conversations? 

The danger here is reductionism: Treating leadership growth like a balance sheet not only oversimplifies things but risks missing the real transformation. Quantitative measures can create a false sense of certainty. A bump in survey scores may reflect genuine growth, or simply a leader who has learned to game feedback. Performance improvements may have as much to do with market conditions as with coaching.

Numbers alone capture the shadow, not the substance. Coaching works in part on the inner theatre of the executive’s mind, where self-awareness, blind spots and unspoken fears reside. To exclude that dimension is like measuring the success of a play by counting ticket stubs while ignoring the performance on stage.

Stories that count

To glimpse the real impact of coaching, you need stories: Colleagues describing how a leader finally listened instead of bulldozing. A team relieved when their manager learned to delegate. An executive who confesses, “I no longer wake at 3.00 am gripped by anxiety.” These stories are evidence of behavioural change, often more reliable than numbers.

As the philosopher John Dewey once observed, “We do not learn from experience, we learn from reflecting on experience.” The best evaluations combine both: numbers for scale and credibility, stories for texture and truth. 

The Executive Coaching Journal

So, how do we make this balance operational in executive coaching programmes? We recommend that coachees keep an Executive Coaching Journal. It is a veritable personal archive of growth documented by both numbers (actions achieved, goals met) and a narratives (stories of transformation). 

The journal should have the following elements: 

1. Growth goal: Executives articulate a specific and concrete growth goal anchored in their professional context. From there, each coaching session is bookended by reflection: preparing beforehand (“What do I most want from this conversation?”) and consolidating afterwards (“What were my key insights?”). 

2. Action log: The journal’s most powerful feature is its action log. Leaders record concrete commitments – delegating a project, initiating a feedback conversation – that would help them reach their growth goal and revisit outcomes at the next session. Over weeks, this becomes a living ledger of evolving behavioural evidence. 

3. Future development plan: At the end, participants revisit their initial goals, assess outcomes, distil key learnings and draft a future development plan. 

Measuring the immeasurable

Consider the example of Sophie, a strategy director in a global manufacturing company who began with the growth goal of shifting her focus from operations to strategy. She wrote in her journal early on in her IEC programme: “I blocked two hours in my calendar to work on strategic issues, but it felt difficult not to get pulled back into my task list when I did it for the first time last Friday.” 

Over time, her entries revealed steady progress as she began using those strategy hours to prepare a three-year roadmap for her division, which she later presented successfully to the board. During her final coaching session, as she reviewed her journal, Sophie was struck by how far she had come, from being constantly caught up in firefighting to thinking and acting strategically. Her boss, who had hesitated to promote her, now put her forward for a senior leadership role.

Or take Raphael, CEO of a tech start-up, who set the goal of managing stress better. In early entries, he recorded frequent moments of tension and conflict affecting his physical well-being. By the third session, he was documenting small wins: “Paused and took a breath instead of snapping.” “Went for a 10-minute walk before dealing with an issue.” 

Subsequent reflections included feedback from colleagues who noticed he was calmer in meetings. By the end of the six sessions, Raphael’s blood pressure was back to normal, a tangible sign of how deeply the changes had improved his well-being. 

Anna’s, Sophie’s and Raphael’s stories are not unusual. Measuring the immeasurable will never be perfect, but with the right blend of rigour and reflection, it becomes not only possible but profoundly valuable for all stakeholders.