The project schedule is a fairly broad and all encompassing concept that while seemingly easy to grasp, must truly be mastered in order for all members of the project staff, from the project management team all the way up to the project management team leader to effectively manage the project in a capable manner from start to finish. The project schedule typically will include all elements of the project from the pre-planning stages of the project through all ongoing project processes that may take place during the active project period, to any and all project related process that may occur at the conclusion and or closing stages of the project. The project schedule network diagram typically refers to a particular input/output mechanism that represents a particular schematic display of any and all logical relationships that may exist between the existing project schedule activities. The project schedule network diagram when properly laid out is always laid in a left to right display to properly reflect the chronology of all project work.
This term is defined in the 3rd and the 4th edition of the PMBOK.