Raffaella Sadun, a professor at Harvard Business School, explains why seemingly common-sensical management practices are so hard to implement. After surveying thousands of organizations across the world, she found that only 6% of firms qualified as highly well-managed — and that managers mistakenly assumed they were all above average. She is a co-author of “Why Do We Undervalue Competent Management?” in the September–October 2017 issue of Harvard Business Review.