CEOs get a ton of credit or blame for a company’s performance. But the entire leadership team is vital to success, and any dysfunction is often overlooked. Sometimes the CEOs leading them don’t even see that they’re not working. Thomas Keil, management professor at the University of Zurich, and Marianna Zangrillo, a partner at The Next Advisors, have interviewed more than 100 CEOs and senior executives. Their research identifies three main types of failing leadership teams: shark tanks, petting zoos, and mediocracies.