A project manager’s goal is to meet the objectives of their projects. The PMBOK® describes three characteristics of an effective project manager—knowledge, performance, and personal. Knowledge refers specifically to knowledge about project management. For example, can the individual develop a project schedule and write a project management plan? Performance refers to what the individual is actually able to accomplish. Is the project moving forward? Personal refers to the individual’s attitude, personality, and leadership. Is the project manager relating effectively to the people with whom they must interact?
The PMBOK also has eight interpersonal skills described in Appendix G that effective project managers possess. These skills are: leadership, team building, motivation, communication, influencing, decision making, political and cultural awareness, and negotiation. Note that many of these directly relate to the ability to influence others to do what is necessary for the project to be successful, which is especially important in that project managers often do not have formal authority over the people with whom they are working.