The assumption that’s limiting your leadership

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Hey Spark Family,

I’ve been thinking about a conversation I had with a leader who had built an exceptional career.

He was decisive, direct, fast, and clear. He had a strong point of view on almost everything, and people found that confidence genuinely compelling. He got things done. He moved quickly through ambiguity. He was, by most measures, exactly the kind of leader organizations reward.

And he was starting to hit a ceiling he could not quite explain.

His team was growing more dependent, not less. Decisions that should have been theirs kept landing back on his desk. The culture he had built was high-performing, but fragile, because so much of it still ran through him.

When we slowed it down, something became clear.

The very qualities that had made him exceptional were now creating some of the friction he was trying to solve.

His speed. His certainty. His ability to cut through complexity and move.

None of those things were wrong. They had served him beautifully.

But complex environments ask something different from leaders. They require more shared thinking, more curiosity, more adaptation, and more capacity to pause long enough for other people to build their own judgment.

The assumption underneath his leadership was simple:

“If I can see the answer quickly, I should move us there quickly.”

That assumption had made him successful.

Now it was keeping his team too dependent on him.

That is one of the hardest parts of growth at a senior level. Sometimes the issue is not that we are doing something badly. Sometimes the issue is that we are doing something well in a context that now needs a more expanded version of us.

The Research Is Clear

Harvard Business Review published an article this year called “To Lead Through Uncertainty, Unlearn Your Assumptions,” and the central idea is one I see constantly in the field.

Leaders are often promoted because they are strong in strategy, execution, communication, and influence. Those are real capabilities. They produce real results.

But in a more complex, fast-changing world, those same strengths can start to hit a ceiling if leaders never examine the assumptions underneath them.

Deloitte’s 2024 Global Human Capital Trends research, cited by HBR, found that organizations need to move beyond old performance measures like efficiency, output, and predictable results. The capabilities that matter now are increasingly human: adaptability, imagination, curiosity, resilience, and steadiness in uncertainty.

McKinsey’s State of Organizations 2026 adds a powerful data point:

➡ Leaders who engage in regular self-reflection are nearly twice as likely to believe their organizations can adapt quickly to change.

➡ 30% of reflective leaders believe their organizations can adapt quickly, compared with 17% of non-reflective leaders.

That gap matters.

Because the most dangerous assumptions in a leader’s repertoire are often the ones that have been proven right before.

Past success makes them feel like facts, not choices.

And that is exactly when they stop being examined.

What I'm Seeing In The Field

The leaders who struggle with this are often the ones with the strongest track records.

Which makes complete sense.

When a way of leading has worked for years, questioning it can feel almost disloyal to yourself. Like you are challenging something you earned.

A leader believes speed is always an asset. And often, she is right. But then she enters a moment that requires the team to slow down and think more deeply. Her pace sends a signal she does not intend to send: we do not have time for that. So the team stops thinking as deeply.

A leader believes having the answer is a sign of competence. Of course he does. He has been rewarded for that his whole career. But now his team hesitates to bring him problems they have not already solved, because they have learned that showing up uncertain feels like falling short.

A leader believes emotional conversations and professional conversations belong in separate rooms. She is strong at both, but her team never sees her bring humanity and accountability into the same conversation, so they do not learn how to do it either.

None of those beliefs are wrong in every context.

That is what makes them tricky.

The issue is when they become automatic. When speed is always better. When certainty is always stronger. When being composed means being disconnected. When the leadership style that got you here starts shaping a culture that is smaller than it needs to be.

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What We Teach Leaders Inside Spark Brilliance

The question I ask leaders who are navigating this is simple, but not always comfortable:

What do you believe about leadership that has never really been tested?

Not the beliefs you have examined and chosen.

The ones you have never had to question because they have always seemed obviously true.

That is usually where the real work is.

Because growth at a senior leadership level rarely comes from adding another tool or framework. The deeper shift often comes from examining something you already believe and asking, “Is this still serving me? Is it serving the people I lead? Is it serving the culture we are trying to build?”

Or has it become a default you reach for without thinking?

The leaders who navigate this well build a regular practice of honest self-reflection.

Where am I assuming I already know the answer?

Where am I moving fast because the situation truly requires speed, and where am I moving fast because slowing down feels uncomfortable?

Where am I providing clarity, and where am I accidentally creating dependency?

Where am I calling something “high standards” that might actually be control?

Those are different things.

And the ability to tell the difference is one of the most valuable things a senior leader can build.

🌟 Your Challenge This Week

This week’s challenge does not ask you to do more.

It asks you to look more honestly.

Think about one belief you hold about how to lead effectively. Something that has been validated by experience. Something that helped you succeed. Something you may not have questioned in a long time because it still feels true.

Ask yourself:

• Where is this belief showing up in how I lead right now?
• What does it produce?
• What might it be costing?
• Does this context need the same version of me that worked before, or a more expanded one?

And the one worth sitting with longest:

Is there a way of leading you have outgrown that you are still carrying because it used to work?

The leaders who keep growing at the highest levels are not the ones with the most answers.

They are the ones willing to keep questioning the answers that once made them successful.

That takes more courage than most people realize.

With gratitude,
​Jackie

P.S. – P.S. If something in this newsletter landed in a way that felt a little uncomfortable, that discomfort is information. It usually means you have located something worth looking at.✨

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