When a schedule is built and changes are made over time (whether with Resources or other areas) and the dates move.  Sometimes unexpectedly.  There are a number of items that could affect this such as Calendars, Predecessors/Successors, Deadlines, Constraints and so on.  One of the fundamental drivers for how the task changes is based upon the task type and how Microsoft Project re-calculates the task.  These task types are duration, work and units.  Even without Microsoft Project, it is good to understand the differences between these task types.

A new White Paper explaining how this works is now on our White Paper section at www.PMPSpecialists.com/WhitePapers.html  Look for the document titled “Task Types – Fixed Duration, Fixed Work, Fixed Units“