Outline tasks into subtasks and summary tasks

You can break down your task list to make it appear more organized and readable by indenting and outdenting the project's tasks to create an outline of the summary tasks (also known as "hammock tasks") and subtasks.

What do you want to do?

Choose a method to organize your tasks

Create summary tasks and subtasks

Learn more about how summary task values are calculated

Why aren't the outline buttons working right?

Choose a method to organize your tasks

When organizing the tasks for a project, you can group the tasks that share characteristics or that will be completed in the same time frame under a summary task. Project managers sometimes call summary tasks "hammock tasks." You can use the summary tasks to show the major phases and subphases in the project. Summary tasks summarize the data of their subtasks, which are the tasks that are grouped beneath them. You can indent the tasks as many levels as needed to reflect the organization of your project.

There are two methods for organizing your task list:

  • With the top-down method, you identify the major phases first and then break the phases down into individual tasks. The top-down method gives you a version of the plan as soon as you decide on the major phases.

    Note   If you can think of tasks that don't fit under the phases that you defined, you are probably missing a phase.

  • With the bottom-up method, you list all the possible tasks first, and then you group them into phases.

After you decide on a method for organizing your tasks, you can begin outlining them into summary tasks and subtasks in Project.

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Create summary tasks and subtasks

Create an outline for your tasks by indenting and outdenting them to create the summary tasks and subtasks. By default, the summary tasks are bold and outdented, and the subtasks are indented beneath them. Keep in mind, that a summary task can also be a subtask of another task above it.

  1. In the Gantt Chart view, click the row for the task that you want to indent as a subtask or outdent as a summary task.

  2. On the Task tab, in the Schedule group, click Indent to indent the task, making it a subtask.

    Task tab Schedule group

Tip    You can indent or outdent a task quickly with the mouse. Point to the first letter of the task name. When the pointer changes to a double-headed arrow, drag right to indent the task or drag left to outdent the task.

Warning    Assigning resources to summary tasks can create unpredictable durations and assignment values. If you have the same resource assigned to the summary task and its subtask, you will not be able to resolve an overallocation if the summary task is automatically scheduled.

In addition, fields such as %Comp are usually used on summary tasks to indicate amount of progress made on all its subtasks. However if there is an assignment on the summary task as well, then the %Comp is used for tracking both the progress made on subtasks *and* progress from that summary assignment. Under these circumstances, Project may not be able track specific progress accurately.


  • To undo outlining, outdent all of the subtasks and lower-level summary tasks until all tasks are at the same outline level.

  • You can easily rearrange the project phases in your outlined schedule. When you move or delete a summary task, you automatically move or delete all the subtasks associated with it.

  • When you delete a summary task, Project will automatically delete its subtasks. To delete a summary task and retain its subtasks, you need to first outdent the subtasks to the same level as the summary task.

  • When you rearrange a task list, the outline numbers for the listed items will change. Outline numbers are updated automatically when you move, add, or delete tasks, because they reflect the current structure of the task list. If you are using a custom numbering system that you entered manually, your numbers are not updated automatically. You need to manually adjust the numbers to reflect the task's new location if you move it.

  • Placing tasks in a hierarchical order does not automatically create task dependencies. To create task dependencies, the tasks must be linked. After you rearrange the linked tasks in your outlined schedule, the task dependencies that you set previously may no longer be relevant, and you may need to update them.

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Learn more about how summary task values are calculated

Not all summary task values show the combined total of your subtask values. Although some summary task values (such as cost and work) represent the total subtask values, others (such as duration and baseline) do not. For example, Project calculates the duration of a summary task as the total work time between the earliest start date and latest finish date of its subtasks.

Summary task

Button image This summary task information summarizes the period between the earliest start date and latest finish date of all the included subtasks. It does not show the sum of all the subtask durations.

Because Project calculates the summary task values, most of them cannot be edited. If you need to change a summary task's values, such as duration, update the individual subtasks. Summary task values are then recalculated.

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Why aren't the outline buttons working right?

There may be a number of reasons why the outlining buttons don't appear to be working correctly.

  • You may be trying to outdent a task that is already outdented as far as possible (or a first-level task)     Tasks at the first outline level cannot be outdented. Instead, indent those tasks that you want to include as subtasks to the first-level summary task.

  • You may be trying to move a task that is contained within a consolidated project (or master project)     When working with consolidated projects or master projects, you cannot outdent a task beyond the level of the subtask of a summary task.

  • You may be trying to indent or outdent assignments, not tasks     The Resource Usage and Task Usage views display task and resource assignments with indentations similar to those of subtasks. Although assignments may be shown or hidden along with subtasks, they cannot be indented or outdented.

  • You may be working in a view that doesn't use the outline buttons     Outline buttons work only when the Gantt Chart, Task Sheet, or Task Usage view is the active view. If you are using one of these views and the outline buttons don't work, make sure that your summary tasks are displayed.

    Click the File tab, and then click Options. On the Project Options page, select Advanced. Under Display options for this project, select the Show project summary tasks check box.

  • You may have your tasks sorted without keeping their outline structure     If your tasks are currently sorted without their outline structure, the outline buttons aren't available.

    To keep the outline structure when sorting your tasks, on the View tab, click Sort in the Data group, and then select Sort By. In the Sort By dialog box, make sure the Keep outline structure check box is selected.

  • You may have your tasks grouped     To remove grouping, on the View tab, in the Data group, click No Group in the Group By box.

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Applies To: Project 2010, Project Standard 2010

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