A Task or Milestone that has no Predecessor or Successor will be identified by this audit. If the option to check selected items only is not checked, all tasks and milestones (summaries are never evaluated in this audit) are tested for this condition.
Why does it matter if items in the project have no Predecessor or Successor?
Dependencies (Predecessors and Successors) are a necessary element of an effective schedule. Without dependencies, the impact of schedule variances may not be known on affected tasks and it will not be possible to perform a credible Critical Path Method (CPM) analysis. If your schedule is visible or reported to certain private and Government organizations, it might not pass audits that test for generally accepted scheduling practices if it contains too many schedule items without predecessors and successors.
To the maximum extent possible, the Start date for a task in a schedule should be determined by its predecessors. The Finish date, I turn, should be determined by its duration - which may need to be adjusted to take into account its successors.
Does every task and milestone in a project need a Predecessor and Successor?
No. It is common for a project to contain certain items that have either no predecessor, no successor or both. Examples of these include:
External inputs (item you receive from sources outside the control of the project). Though external inputs should have one or more successor, they often do not have a predecessor. If an external input does not have a successor, it is give a Start Date Constraint that reflects the anticipated date of receipt for the item.
External outputs (end item deliverables). External outputs should have predecessors but may not have a successor.
Task that represents the supporting or sustaining role of an individual or function on a project. A common name for this type of task is “Level of Effort” abbreviated as “LOE”. Since LOE should not drive the schedule and should not appear on a Critical Path Method analysis, it is often recommended, if these are even included in a schedule, to schedule these items without using predecessors or successors.
Resolving tasks with No Predecessors or Successors
Perform the Audit and Click on each item in the resulting tasks list to go to the offending task. You can also click Filter for Items Below to display tasks with audit issues and record the offending condition in the Integrity Note log field.
Schedulers should work directly with subject matter experts and the project team to examine work flow and life cycle models that are applicable to the project, then add the necessary predecessors and successors.
What Else to Consider
Project Management Institute's PMBOK (Project Management Body of Knowledge) definition of Predecessor and Successor Activity:
Predecessor Activity: The schedule activity that determines when the logical successor activity can begin or end
Successor Activity: The schedule activity that follows a predecessor activity, as determined by their logical relationship
The DCMA 14 Point Assessment tests for "Missing Logic"
Missing Logic: Number of activities missing a predecessor, a successor, or both. Should not exceed 5%.
