Data Type Number (number field: A type of field whose content is a number. The maximum value allowed in this field is 999,999,999,999.99.)
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 Task Outline Number field contains the number that represents the associated 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 task 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.) code, except that the task outline number is automatically entered by Project.
How Calculated Project assigns the assignment's outline number according to the associated 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. The next 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 Task Outline Number field to the Resource Usage view when you want to display the position of an assignment's task within the project's outline structure. If you use the outline numbers as WBS codes, this can help you identify tasks by number.
Example When reporting on assignment progress, you prefer to use the outline numbers rather than the task names. You add the Task Outline Number field to the Resource Usage view to see the outline numbers.
Remarks The Task Outline Number field is available only in the Resource Usage view, and not in the Task Usage view.