Summary Tasks

If a task has child tasks, then it is called a summary task. Many attributes of summary tasks are rolled up from its child tasks. Some of the non trivial attributes are described below.

Start Date (planned/actual/projected)
It is the minimum of planned/actual/projected start date of its children.

Finish Date (planned/actual/projected)
It is the maximum of planned/actual/projected finish date of its children

Work (Effort)
It is the sum of work of its children.

Constraints
Constraints are not applicable for summary tasks.

Resource allocation
Resources assigned to a summary task will not be factored into the planned cost of the summary task, nor displayed on the resource load charts.

% Complete

% Complete = (W1×P1 + W2×P2 + ... + Wn×Pn) ÷ (W1 + W2 + ... + Wn)
For all n leaf-level descendants where Wi is the work and Pi is the % complete of its ith descendant.

Predecessors
If a summary task has a predecessor, the system considers it to be equivalent to having that predecessor for all its children.

Auto/Manual Scheduling
Since the planned start and finish are calculated from its children, summary tasks are always considered to be auto scheduled.

Budget/Costs/Billing
It is the sum of the budget/costs/billing of its children.

Duration
It is the working time between the task's start and finish date as per the project's work calendar