top of page

6 Fatal Flaws that Kill a Leader's Effectiveness

Finding Fatal Flaws

Chances are you’ve known or read about great leaders and learned that they have weaknesses. From that, you have concluded that you don’t have to be perfect to be a great leader.

In the research my colleague Joe Folkman and I conducted, we too have found that mild weaknesses do not appear to erode an exceptional leader’s effectiveness. Our research highlighted, however, that there was a difference between a mere weakness and a fatal flaw. A fatal flaw is a significant weakness that goes beyond merely diminishing a leader’s effectiveness. A person with a fatal flaw was never among the most effective leaders in the organization. Weaknesses can be overlooked. Fatal flaws form such a strong negative impression, they cannot be ignored.

Recently, we were certifying a group of coaches who support a leading university’s Executive Education program. We explained our definition of a fatal flaw as a competency on which a leader had a score at or below the 10th percentile. One of the coaches posed an excellent question, “On which competencies do fatal flaws most frequently occur?”

A Comparison with World Health

Six diseases are responsible for a large percentage of deaths around the world. Heart disease and stroke account for more than half of all deaths. Then pulmonary diseases, Alzheimer’s, cancer and diabetes follow. If the goal is to diminish the death rate, these are the diseases on which to focus.

What are the comparable areas of leadership behavior that account for the greatest numbers of leadership failures?

Identifying the Most Frequent Leadership Failures

We examined data from over 87,000 leaders. The data was from a 360 assessment where leaders from across the globe were evaluated by (on average) 13 other people.

In our original research, we identified a profound strength as a competency at the 90th percentile. We decided to apply the same logic at the other end of the scale. We identified those behaviors at or below the 10th percentile as fatal flaws. We calculated the 10th percentile mean score for each of the competencies we measured and then created an overall 10th percentile average score.

Using this 10th percentile average score as the general cut-off score for fatal flaws, we then identified which competencies had the highest and lowest frequency of people in this fatal flaw range.