The Line Through Leadership Data

In more than twenty years advising executives and coaching leaders through succession, transformation and the occasional quiet crisis, the problem I meet most often is not incompetence. It is confusion. A capable leader is handed three readings of the same gap, from the board, from a 360 report, from their own instinct, and none of them agree. The hardest part of leading well is often just working out which signal to believe.

Three leaders, one problem

Consider three leaders you might recognise, perhaps from your own week.

Leader A has just been told by his board that he has a gap in strategic influence. He is blindsided. From where he sits, he has delivered every number he was asked to. Is the board seeing something real, or reacting to a style they simply do not warm to?

Leader B senses that something is wrong in how she is running her team. Engagement feels thin and good people are quietly checking out. Yet her latest 360 came back warm and reassuring. Her instinct says one thing, the feedback says another.

Leader C built his career on decisiveness in a stable market. The market is no longer stable. In a faster, more ambiguous environment, the very behaviours that made him successful may now be working against him, and no feedback he receives is quick enough to tell him.

Three situations, one shared predicament. Each leader is trying to reconcile what others say about them with what they believe about themselves, and neither source is solid enough to act on with confidence. This is the daily reality of leadership, and it is where the trouble starts.

And it does not stay personal. A leader's blind spots do not stop at the office door. Gallup's analysis of 2.7 million employees found that managers alone account for roughly 70 percent of the variance in their team's engagement (Gallup, 2015), and engagement in turn tracks with productivity, retention and profitability. A leader who doubts the wrong things, or is blind to the right ones, is not carrying that uncertainty alone. It is quietly priced into the performance of everyone they lead. For the organisation, unclear leaders are expensive in ways that never show up on a single line of the budget, which is precisely why the person reading this is rarely deciding only for themselves. Leaders are the organisation's instrument for reading other leaders too.

There is a line running through leadership data

Every piece of information you hold about your own leadership, or anyone's, sits on one side of a line. Below the line is what people say: the board's read, the 360, the references, and the leader's own self-assessment. Above the line is what a person demonstrably does, their behaviour, observed directly and measured against a standard. The distinction sounds academic until you are Leader A, B or C, or until you are the one deciding their future. Then it is everything, because below the line you are navigating by opinion, including your own, and above it you finally have a signal you can trust.

Why you cannot fully trust the feedback, or your own read

Start with the uncomfortable part: a person's view of themselves is a weak instrument. When researchers compared self-assessments of ability against objective measures of performance across 55 studies, the average correlation was only about r = .29 (Mabe and West, 1982), a faint signal to steer a career, or a succession decision, by. And it is not random noise. Leaders whose self-view lines up with how others actually see them tend to perform better, while those who over-rate themselves, the ones with the largest blind spots, tend to perform worse (Atwater and Yammarino, 1992). Self-awareness is not a soft virtue. It is a measurable performance variable.

The external feedback is not much firmer. Multisource, or 360, feedback is useful, but on its own it rarely changes behaviour: the most cited meta-analysis found the average improvement afterwards is small (Smither, London and Reilly, 2005). Feedback tells Leader B she is doing fine while her instinct says otherwise. It tells Leader A he has a gap without telling him what, specifically, he does that creates it. Both are left holding opinions.

Below the line, you learn what people believe about a leader, including what the leader believes about themselves. Above it, you learn what they actually do.

As a coach, this is the knot I untie most often. A leader arrives with a fistful of contradictory feedback and a self-image that may or may not be accurate, and the first, most expensive weeks go on simply establishing what is true. Coaching works, and the research is clear that self-awareness and openness to feedback are its active ingredients (Bozer and Joo, and the wider coaching literature). But it works far faster when it starts from an objective picture of behaviour rather than a negotiation between competing opinions.

And this is not a small or cheap problem for the organisations paying for it. Executive and business coaching is now a multi-billion dollar industry, on the order of 4.5 billion US dollars a year worldwide and growing fast (ICF Global Coaching Study, 2023). Yet the organisations that fund it routinely struggle to prove what they bought, because coaching's return is famously hard to measure. Part of the reason sits exactly here: when coaching begins from contested feedback and a leader's own uncertain self-image rather than from an objective read of behaviour, there is no clean baseline to measure change against, and no shared starting point the leader can readily accept. Organisations are buying development without a diagnostic. That is a great deal of money spent reconciling opinions that one honest measurement could have settled in an afternoon.

What you can trust, and how it helps you grow

Above the line is harder to reach, which is why it is rare. It means observing what a leader actually does, in conditions realistic enough to matter, and scoring that behaviour to a consistent standard. The evidence says the effort pays: structured, behaviour-based methods such as assessment simulations predict later performance markedly better than self-report, with meta-analytic validity around r = .37 for assessment centres (Gaugler and colleagues, 1987). Watching what someone does under realistic pressure is simply better evidence than anything they, or anyone else, can say afterwards.

For a leader, this is not a threat. It is the most useful mirror you will ever hold. Development that starts from an accurate baseline moves faster than development that starts from an argument. Give Leader A objective evidence of how he actually behaves in a high-stakes strategic exchange, and the board's vague influence gap becomes a specific, workable thing. Show Leader B what really happens in the moments she leads her team, and her instinct is either confirmed or corrected; either way she can finally act. Let Leader C see which of his instincts still serve him in a volatile scenario and which now cost him, and he can adapt on purpose rather than by trial and error.

It also compounds. Because a leader sets the weather for everyone beneath them, the return on one leader seeing clearly does not stay with that leader; it spreads across a whole team, and up through every succession and hiring call they will make. This is the shift worth naming: an objective read of behaviour is as much a development tool as a diagnostic one, and as much an organisational asset as a personal one. The leaders who grow fastest, and the organisations that pick leaders best, are not the ones with the most feedback. They are the ones who trust an accurate picture enough to act on it. Evidence is what turns self-doubt into a plan.

Why now

The timing is not incidental. Organisations pour enormous sums into developing and selecting leaders, roughly 400 billion US dollars a year in corporate learning alone (The Josh Bersin Company, 2026), yet most employers still name leadership and skills gaps as a major barrier to transformation (World Economic Forum, 2025). The money proves the intent. The persistent gaps prove that the measurement underneath it has not kept pace. In a world changing as quickly as Leader C's, steering development, your own or your organisation's, by opinion is a slower and riskier bet than it has ever been.

An honest mirror

One honesty, so the claim is clean. Measuring leadership from behaviour is a discipline still being built, and the instruments that do it, including ours, have to earn their authority through validation against recognised standards, over time. This is a mirror, not a verdict on anyone's worth, and a good mirror is candid about its own making. Tessadi is building Veridessa to be exactly that: an objective, evidence-based read of how a leader actually leads, so that the leader, the coach in their corner, and the board deciding their future can all start from what is true. We are not trying to build a better tool below the line. We think the line is the whole point, and that the leaders who cross it, and the organisations that insist on it, are the ones who get better fastest.

References

1. Mabe, P. A., & West, S. G. (1982). Validity of self-evaluation of ability: a review and meta-analysis. Journal of Applied Psychology, 67, 280-296.
2. Atwater, L. E., & Yammarino, F. J. (1992). Does self-other agreement on leadership perceptions moderate the validity of leadership and performance predictions? Personnel Psychology, 45, 141-164.
3. Smither, J. W., London, M., & Reilly, R. R. (2005). Does performance improve following multisource feedback? Personnel Psychology, 58, 33-66.
4. Gaugler, B. B., Rosenthal, D. B., Thornton, G. C., & Bentson, C. (1987). Meta-analysis of assessment center validity. Journal of Applied Psychology, 72, 493-511.
5. Gallup (2015). State of the American Manager. Managers account for roughly 70 percent of the variance in team engagement.
6. International Coaching Federation (2023). ICF Global Coaching Study. Global coaching revenue estimated at 4.56 billion US dollars, up 60 percent since 2019.
7. Bozer, G., & Joo, B. K. Research on coachee characteristics, feedback receptivity and self-awareness in executive coaching. Exact citation to be finalised before publication.
8. The Josh Bersin Company (2026). AI is disrupting the 400 billion dollar corporate training market.
9. World Economic Forum (2025). Future of Jobs Report 2025.