Are you responsible for implementing a major change? Is everyone sold on the idea and actively supporting it? Change isn’t easy for people, but people are critical to the success of change. In fact, failure to gain their buy-in is the No. 1 reason why initiatives and projects fail. When leaders understand the theory of change and adopt the right constructs, skills, behaviors and tools, then they are able to influence those people positively and move the mountains they need to move.