Why Top Performers Fail as Managers

You promoted your top salesperson. Six months later, the team is missing targets, and they’re quietly miserable. You made your best engineer the lead. Now, nobody can get a decision out of them. 

The person you counted on most has become your most urgent problem. 

This happens so often it has a name.

There’s A 55-Year-Old Explanation For This

In 1969, Dr Laurence J. Peter observed that people in hierarchies get promoted based on how well they perform in their current role, until they land in a role where they don’t. He called it the Peter Principle: employees rise to their level of incompetence. 

Half a century later, the pattern plays out in organisations everywhere. The reason isn’t careless leadership. It’s that most organisations are using the wrong data to make promotion decisions, and don’t realise it.

What Most Organisations Actually Do When a Management Role Opens Up

They look at who’s performing best. They run a few interviews. A senior leader makes a call based on gut feel and track record. The top performer gets the job. 

Every step of that process measures the same thing: how good this person is at their current role. 

The problem is that performance in a current role is a poor predictor of success in a fundamentally different one. Schmidt and Hunter’s meta-analysis of 85 years of selection research found that unstructured interviews (the default in most promotion processes) have a validity of just 0.38 for predicting job performance. Work experience and education score even lower at 0.18 and 0.10, respectively. These are the primary signals most organisations rely on to make one of their highest-stakes talent decisions. 

Why The Skills Don’t Transfer

Being exceptional as an individual contributor requires deep expertise, personal accountability, and independent execution. Management requires delegating work you could do better yourself, developing people who aren’t yet performing, and getting results through others when your entire career has been built on getting them yourself. 

These are not extensions of the same skills. They are a different job with a different psychological profile. 

A high performer who struggles to let go of the work, who finds giving structured feedback uncomfortable, or whose motivation is driven by personal achievement rather than team outcomes, will underperform as a manager regardless of how talented they are. None of that is visible in their sales numbers or their output.

What The Data-Driven Version Looks Like

The organisations that consistently get this right separate two questions that most conflate. 

How well is this person performing in their current role? Performance reviews answer this. 

What is this person capable of doing in a fundamentally different role? Only objective potential assessment answers this, and most organisations skip it entirely.

Before a promotion decision, three things need to be measured:

Learning agility
How quickly can this person develop effective new behaviour in unfamiliar territory? The first six months of any management role are entirely unfamiliar. De Meuse’s (2019) meta-analysis of 20 field studies found that learning agility has a robust relationship with leader performance (0.74) and leader potential (0.75), making it one of the strongest individual predictors of leadership success in the research literature.* 

Competency potential
Does this person have the behavioural capacity for the specific demands of the management role? This measures their potential against the actual competencies required to manage that team, at their level. 

Motivational fit
Does this person actually want to manage people? Most organisations never ask this with any rigour. High performers promoted against their natural motivational profile burn out or disengage, a loss on both sides.This is exactly what Lumenii’s psychometric assessments are built to surface, before the promotion, not after the fallout. The Select assessment measures cognitive ability, learning agility, and the behavioural profile required for leadership, giving you the data point your performance review was never designed to produce.

The Conversation Most Managers Never Have

With that data, you can have a different kind of promotion conversation, one that goes beyond “you’ve earned this” to “here’s what this role requires, here’s what the assessment shows about your fit for it, and here’s what development would bridge the gap.” 

Some of your best contributors, given the space to answer honestly, would rather stay in a senior individual contributor track. Keeping a high performer in the role where they thrive is a better outcome than promoting them into one where they won’t. 

The Peter Principle persists because organisations keep feeding it the same inputs. Performance data tells you who’s winning today. Potential assessment tells you who’s built for what comes next. Using both is how you develop great managers without losing great contributors. 

References

De Meuse, K.P. (2019). A meta-analysis of the relationship between learning agility and leader success. Journal of Organisational Psychology, 19, 25–34. 

Schmidt, F.L., & Hunter, J.E. (1998). The validity and utility of selection methods in personnel psychology: Practical and theoretical implications of 85 years of research findings. Psychological Bulletin, 124(2), 262–274.