Well duh? Of course effective leadership matters. Did we need a study to tell us this? Actually, we probably did. For some reason, we are predisposed to give people positions of power and authority without any training in management and leadership. Development Dimensions International published their 2011 study on leadership. You can read a good blog summary of the findings here.
“The research demonstrated that organizations with the highest quality leaders were 13 times more likely to outperform their competition in key bottom-line metrics such as financial performance, quality of products and services, employee engagement, and customer satisfaction.”