If you want your organization to thrive in a complex, fast-changing world, you can’t leave leadership growth to chance. Yet that’s exactly what many companies still do. They are relying on formal training sessions alone to “build” leaders. The truth? Developing the next generation of leaders isn’t just about courses. It’s about creating environments where people learn through experience, reflection, and real-time feedback.

This is where the 70:20:10 concept offers a helpful perspective. It reminds us that most learning happens on the job. About 70 percent through doing, experimenting and stretching into new challenges. Around 20 percent comes from others through coaching, mentoring, and collaboration. And roughly 10 percent comes from formal training like structured programs, workshops and courses.

While the model itself isn’t a scientific law (and was never meant to be), it captures an intuitive truth: learning is continuous, contextual, and deeply personal. Real growth happens when people apply ideas in the flow of work, not just in the training room or the Zoom.

So why does this matter for developing tomorrow’s leaders? Because today’s emerging professionals are being asked to lead in conditions their predecessors never faced:hybrid workplaces, multi-generational teams, digital acceleration, and rising expectations for inclusion and agility. They need development that mirrors reality: practical, people-centered and integrated into their day-to-day responsibilities.

Formal training still plays a critical role but only when it’s timely, relevant, and reinforced through experience. As the original Lessons of Experience study noted, executives reported that coursework had real impact when it dealt with a relevant issue and came at the right time. That’s the sweet spot.

To truly optimize organizational performance, we must think beyond programs and focus on performance ecosystems i.e. environments that enable learning everywhere. That means pairing formal development with coaching, providing stretch assignments with feedback loops, and fostering psychological safety so experimentation is encouraged, not penalized.

When we do this, leadership development stops being a box to tick and becomes a living system, one that builds confidence, capability, and culture all at once.

Because the real question isn’t “How much should we train?” It’s “How are we creating the conditions for people to continuously grow?”

That’s how you future-proof the success of your talent and your organization.