William Deming, one of the leading figures in management, coined the famous phrase that inspired the title of this article. In its full version, it states: “You cannot manage what you do not measure; you cannot measure what you do not define; you cannot define what you do not understand; and there is no success in what is not managed.” In other words, to achieve success, we must first understand, then define, measure, and ultimately manage.

This statement has always applied to business metrics, and in today’s world—where data is abundant—it is nearly impossible to think about management without some form of measurement. But what if we reverse this logic and apply this thinking to the leader themselves?

How can we understand, define, measure, and then manage the leader?

For this exercise, let’s consider first-time leadership—the transition from individual contributor to leader is a crucial moment in any career. While exciting and rewarding, it is also filled with challenges. Last year, Forbes published an interesting article on these challenges¹, but perhaps did not address the central aspect: how do we manage this leader? Following Deming’s logic, the first two steps are to understand and define.

Understand and Define

Through first-time leadership assessment, we can measure these important variables and build a comprehensive profile of that leader, providing valuable input for development and improvement actions. However, the measurement and analysis process must be scientifically grounded and methodologically robust, which requires a strong body of knowledge and extensive experience in the field.

When well designed and executed, first-time leadership assessments make it possible to evaluate an individual’s potential to excel in leadership roles. They go beyond résumés and interviews, providing a deeper understanding of the traits and competencies that define a leader in today’s world.

When this type of assessment is conducted properly, we can make better succession and hiring decisions, develop leaders in a more targeted way, enhance leaders’ self-awareness, and consequently improve team performance. With this data in hand, managing first-time leaders should be approached in a way that prepares them not only for current challenges, but especially for future ones.

Leadership development is only effective when it is data-driven, and the best source of data in this case is first-time leadership assessment.

Conclusion

Given all the current challenges of first-time leadership and organizations in general, the costs and risks of an unprepared or poorly managed first-time leader are prohibitive. The very competitive survival of the organization may be at stake when first-time leaders are not properly assessed and prepared.

In this context, it is crucial for companies to adopt first-time leadership assessment as part of the management cycle, avoiding misguided decisions and contributing to the organization’s sustainable positive performance.