About task types

Microsoft Office Project 2003 uses one of three task types (task type: A characterization of a task based on which aspect of the task is fixed and which aspects are variable. There are three task types: Fixed Units, Fixed Work, and Fixed Duration. The default task type in Project is Fixed Units.) to calculate the duration of tasks and subsequently their finish dates (finish date: The date that a task is scheduled to be completed. This date is based on the task's start date, duration, calendars, predecessor dates, task dependencies, and constraints.) (or their start dates (start date: The date when a task is scheduled to begin. This date is based on the duration, calendars, and constraints of predecessor and successor tasks. A task's start date is also based on its own calendars and constraints.) if you schedule your project from the project finish date rather than the project start date).

For all tasks, after you assign a resource, the task is scheduled according to the formula Duration = Work / Units. For any task, you can choose which piece of the equation Project calculates by setting the task type.

The three task types are fixed units (fixed-unit task: A task in which the assigned units [or resources] is a fixed value and any changes to the amount of work or the task's duration do not affect the task's units. This is calculated as follows: Duration x Units = Work.), fixed work (fixed-work task: A task in which the amount of work is a fixed value and any changes to the task's duration or the number of assigned units [or resources] do not affect the task's work. This is calculated as follows: Duration x Units = Work.), and fixed duration (fixed-duration task: A task in which the duration is a fixed value and any changes to the work or the assigned units [that is, resources] don't affect the task's duration. This is calculated as follows: Duration x Units = Work.). Project uses fixed units by default.

Each of the task types affects scheduling when you edit one of the three elements as follows.

In a... If you revise units... If you revise duration... If you revise work...
Fixed-units task Duration is recalculated. Work is recalculated. Duration is recalculated.
Fixed-work task Duration is recalculated. Units are recalculated. Duration is recalculated.
Fixed-duration task Work is recalculated. Work is recalculated. Units are recalculated.
 
 
Applies to:
Project 2003