Data Type Text (text field: A type of field whose content is text. Examples include the Task Name and Email Address fields. This field can contain up to 255 characters.)
Entry Type Calculated (calculated field: A field in which the value is determined by Project based on information in other fields. Project may recalculate the value automatically or when you specify, depending on your choice of calculation settings.)
Description The Outline Number field contains the number that represents a task's position in the hierarchical outline (outline: A hierarchical structure for a project that shows how some tasks fit within broader groupings. In Project, subtasks are indented under summary tasks.) structure. The outline number is similar to a work breakdown structure (WBS) (WBS: A hierarchical structure that is used to organize tasks for reporting schedules and tracking costs. With Project, you can represent the work breakdown structure by using task IDs or by assigning your own WBS code to each task.) number, except that the outline number is automatically entered by Project.
How Calculated Project assigns the Outline Number according to the task's sequence and outline level in the project outline hierarchy. The first task has an outline number of 1. The subtask (subtask: A task that is part of a summary task. The subtask information is consolidated into the summary task. You can designate subtasks by using the Project outlining feature.) that appears directly under that first summary task (summary task: A task that is made up of subtasks and summarizes those subtasks. Use outlining to create summary tasks. Project automatically determines summary task information [such as duration and cost] by using information from the subtasks.) has an outline number of 1.1. Another subtask on the same level has an outline number of 1.2. The first subtask of that subtask has an outline number of 1.2.1. A task with an outline number of 7.2 indicates that it's the second subtask under the seventh top-level task.
Best Uses Add the Outline Number field to a task view when you want to display the position of a task within the project's outline structure. You can also use outline numbers as WBS codes, which identify tasks by number and indicate the tasks' positions within the project.
Example When reporting on task progress, you prefer to use the outline numbers rather than the task names. You add the Outline Number field to the Task Sheet view to see the outline numbers.
Remarks You can specify that the outline number be displayed in the task sheet beside the task name in the Project Options dialog box.