Summary Task
A summary task is a parent row that represents its children as a group. Its start, finish, and progress are derived from the children, never entered directly.
What it groups
A summary task is a parent row that represents its children as a group. In a WBS, the Phase and Deliverable nodes play this role; on a Gantt chart it is drawn as a thick bar spanning its children's bars. The actual work happens in the lowest-level Work Packages — the summary task is the vessel that rolls their results up the hierarchy. Depending on how deep you collapse the tree, it serves as a one-line executive summary or a team-level status board.
Why it matters
A summary task's start, finish, duration, and progress are derived from its children, not entered directly. The start is the earliest child start, the finish the latest child finish, and progress rolls up along the weights. Because of this derivation, one entry at the lowest level refreshes every summary above it, and the numbers agree at whatever height of the hierarchy you read them. Only when the summary is automatic do the report and the floor share the same figures.
Common misconceptions
The most common mistake is typing dates or progress directly into a summary task. Overwriting a derived value by hand makes parent and children tell different stories, and no one can say which is true. Duration is misread just as often: a summary task's duration is not the sum of its children's durations but the span from the earliest start to the latest finish. With children running in parallel, tasks totaling 30 days can finish within a 12-day span. Finally, hanging real work directly on a summary task leaves that scope belonging to no child, which blurs the 100% Rule.
wbsgantt derives a summary node's start, finish, duration, and progress entirely from its descendants and takes no direct input; the duration shown is the span in working days, not the sum of child durations.