Take two people through the same MBA, the same graduate scheme, the same eight years at the same firm under the same managers.
Put them in equivalent roles and watch for a year. They will lead almost nothing alike.
This is so ordinary that we rarely stop on it. But it should bother anyone who works in leadership development, because it means the input we spend most of the money on is not the main variable.
The missing term
Development treats people as roughly interchangeable material. Apply the training, get the leader.
If that were true, common training would produce convergent styles. It does not — it produces divergent ones. Which tells you that what people bring to the training matters more than the training does.
Everyone knows this informally. It is why "she was always going to be good" is such a common thing to say about a strong leader, and why nobody finds it strange.
What is strange is how little of our development effort is aimed at that starting material.
Three ways the same input diverges
The same advice costs different people different amounts. "Be more direct" is a small adjustment for one person and a fortnight of dread for another. Same instruction, wildly different price. Programmes price it as though it were the same.
The same strength is reached by different routes. Two leaders both hold a team steady in a crisis. One does it by being visibly calm and absorbing the anxiety. The other does it by being relentlessly concrete — next step, then the next. Same outcome, opposite mechanisms. Teach the first person's method to the second and you get a worse version of both.
The same weakness has different causes. Two leaders avoid conflict. One is conflict-averse and needs to build tolerance for it. The other is not conflict-averse at all — she is over-loyal, and protects people past the point of usefulness. Identical symptom, and the remedy for one makes the other worse.
Generic development cannot make these distinctions. It is not designed to.
Why this matters more for founders and directors
Junior roles are constrained enough that individual variation matters less. The role holds the shape.
Seniority removes the constraints. Nobody is telling a founder how to run her week. At that level the person is the method, and the variation that was previously absorbed by the role is now fully expressed — in the strategy, the hiring, the culture, all of it.
This is exactly the point at which most development becomes more generic, not less. The senior programme, the leadership retreat, the peer group of twenty. It runs backwards.
The practical consequence
Before you take on any development, know your own starting material. Specifically:
What do you do without effort that others find difficult? What have you been criticised for repeatedly across different contexts? What kind of pressure degrades your judgement, and what kind sharpens it? Which advice have you received twice and rejected twice, and were you right to?
With that, you can filter. You take the parts of the training that fit your grain and build them properly, and you politely leave the parts that were calibrated for a different person.
Without it, you take everything at face value, spend two years converting yourself towards an average, and arrive somewhere that no longer suits you.
Same training. The difference was never the training.