Although everyone agrees that hiring is tough, most managers struggle with an even more prevalent leadership mistake. It’s an affliction as prevalent as the common cold, and one of the least recognized in the workplace today.

Over the last 20 years at ghSMART, we have been able to empirically observe where executives excel and where they get in their own way. We have conducted five-hour interviews with more than 15,000 leaders across every major industry, producing more than 9 million data points.

So, what is the No. 1 most common mistake that holds leaders back?

The complete inability to remove underperformers.

And why do we all struggle with this? Here are the top five reasons that we see:

  1. You are an eternal optimist. You somehow believe that you will fix poor Mark in Finance or Emma in Marketing. Or, even better, perhaps they will magically fix themselves.
  2. You don’t want to rock the boat. You believe in accepting the cards that you are dealt. You have been taught to make do. As kids learn at daycare today, “You get what you get and you don’t get upset.”
  3. You dislike conflict. Difficult conversations are difficult. So it is easier to suffer through it even if your whole team can now get less done.
  4. You will look bad. You may have hired or promoted them into the role. You don’t want to just pass the buck.
  5. You excel at procrastinating. Why do today what can safely be put off for another day? Besides, who knows? He or she might resign, and that would make it easier for everyone.

You may suffer from just one, or more likely a combination, of these reasons.

And yet our research found that executives who excelled at removing underperformers from their teams are more than twice as likely to have had a successful career than all other senior leaders.

Yes, that’s right: twice as likely. The best leaders we meet tell us that it makes all the difference.

Panos Anastassiadis is one who does it very well. He was the CEO of Cyveilance, which grew over 1500% in five years. His secret? “I have simply been constantly averaging up who is on the team.”

Yet how do you do that and still do right by the individual in question?

You can set them clear goals and craft the role to play to their strengths. But when it clearly isn’t working, it’s time to take action. Run a fair, objective talent management process, tell them that their performance isn’t where it needs to be and give them 30, 60 or 90 days to turn their situation around.

If that doesn’t work, it’s time to have that tough conversation that deep down you know you should have had six, 12 or maybe 24 months ago.

Once done, yet only then, can you hire that A player you really need.

Geoff is Chairman & Founder of ghSMART. Geoff is co-author, with his colleague Randy Street, of the New York Times bestselling book Who: The A Method for Hiring and the author of the #1 Wall Street Journal bestseller Leadocracy: Hiring More Great Leaders (Like You) into Government. Geoff co-created the Topgrading brand of talent management. Geoff is the Founder of two 501c3 not-for-profit organizations. SMARTKids Leadership Program™ provides 10 years of leadership tutoring and The Leaders Initiative™ seeks to deploy society’s greatest leaders into government. Geoff earned a B.A. in Economics with Honors from Northwestern University, an M.A., and a Ph.D. in Psychology from Claremont Graduate University.