The Domain Size Theory

Traditionally, we use two signals to judge how senior a leader is:

Title
Org size

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How big is the team?
How many people report to them?

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That made sense.

Because in the past,

problem size scaled with team size.

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Bigger problem → more people
More people → more senior leader

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That mapping is breaking.

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With AI,

small teams can now handle much larger domains.

Fewer people,
but significantly more complexity.

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You can already see it:

Small startups building products
that compete with much larger organisations

Leaders owning end-to-end systems
that used to require multiple teams

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So the signal is shifting.

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It’s less about how many people you manage.

It’s more about what you own.

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Not tasks. Not projects.

Problem domains.

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For example:

Owning whether an entire product ecosystem stays up or breaks

Owning how customer needs become real products

Owning how products connect, evolve, and scale across the company

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These are large surfaces of complexity.

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But there’s a more personal signal.

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You know your seniority is increasing when:

important problems
cannot bypass you

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When your input is needed
before decisions are made

When your judgment shapes the direction

When your absence creates a gap

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That’s not about control.

It’s about ownership.

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Not headcount.

But domain size.