The Task Summary Name field contains the names of the summary tasks (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.) for the task associated with a resource assignment.
There are several categories of Task Summary Name fields.
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.)
Task Summary Name (resource field)
Entry Type Null (Null field: A field that displays no actual information but that sets up the field for information elsewhere in the view, particularly in the Task Usage or Resource Usage view.)
Best Uses Add the Task Summary Name field to the sheet portion of the Resource Usage view when you want to see the names of the immediate summary tasks associated with a resource's individual assignments. This field is available only in the Resource Usage view. Because the Resource Usage view does not show a task's summary task (unless a resource is assigned to a summary task), the Task Summary Name field can be useful to see the larger context of a task assignment. This is especially useful when there are tasks by the same name under different summary tasks. No information appears in the Task Summary Name field next to the resource names. However, the summary tasks for their corresponding assignments appear in the Task Summary Name assignment fields below each resource name.
Example Your project includes the construction of Building E and Building F. In a task sheet, you have designated Building E and Building F each as summary tasks, with a number of identical subtasks, such as "Build floor" and "Build walls" beneath both summary tasks. You are reviewing assignments for resources on this project in the Resource Usage view. The task names appear in the assignment rows. You want to see the names of the summary tasks associated with the assigned tasks so you can see which building the tasks are associated with. You add the Task Summary Name field to the view.
Task Summary Name (assignment field)