There are five reasons that large projects fail. Wrong projects are ones that defy conventional business rationale, creating outputs that either few people want, that add little to no real value, or that undershoot the desired benefits because they are so difficult to achieve. A second reason is unreasonable constraints — when the effort doesn’t have adequate funding, people, time, or other key inputs. Lack of effective leadership is another project killer, as is undue complexity, where projects span multiple teams, business units, geographies, and organizations and face volatility, uncertainty, and ambiguity. A final obstacle to project success is too much or too little management. To avoid these pitfalls, smart companies should hire senior executives who are project management experts, commit to clear processes and strong governance, and empower project managers.