Project Managers have always been taught to focus on the Triple Constraint, Time, Cost, and Scope. That is a good thing as in order to successfully manage a project it is important to plan for, execute, and track these variables. This focus has been reflected in PMBOK®s from the 1st through the 6th edition with PMI® taking a prescriptive approach to generally accepted project management practices. As such, the PMBOK® editions have had an emphasis on predictive and iterative life cycles which usually follow a waterfall sequence of project phases. In the 7th edition of the PMBOK®, PMI® decided to change the focus of the material to an outcome based format, more in line with ANSI, and ISO standards. The focus is now on Project Management Principles and Performance Domains that are relevant to any project management life cycle.
