Comprehensive Project Scheduling Glossary: Essential Terms Explained

Crashing

Crashing is a schedule compression approach that adds more resources to activities on the critical path to complete the project earlier. When crashing a project, costs are added because the associated labor and sometimes resources (such as faster equipment) cause an increase in costs.

Critical Path

The critical path in the project network diagram cannot be delayed, otherwise the project completion date will be late. There can be more than one critical path, and activities in the critical path have no float.

Discretionary Dependencies

These dependencies are the preferred order of activities. Project managers should use these relationships at their discretion and should document the logic behind the decision. Discretionary dependencies allow activities to happen in a preferred order because of the best practices, conditions unique to the project work, or external events. The preferred order can also be known as preferential or soft logic.

Early Finish

The earliest a project activity can finish. Used in the forward pass procedure to discover the critical path and the project float.

Early Start

The earliest a project activity can begin. Used in the forward pass procedure to discover the critical path and the project float.

Fast Tracking

Fast tracking is a schedule compression method that changes the relationship of activities. It allows activities that would normally be done in sequence to be done in parallel or with some overlap. Fast tracking can be accomplished by changing the relation of activities from FS, to SS, to FF or by adding lead time to downstream activities. However, fast tracking does add risk to the project.

Finish-to-Finish

Finish to finish is an activity relationship type that requires the current activity to be finished before its successor can finish.

Finish-to-Start

Finish to start is an activity relationship type that requires the current activity to be finished before its successor can start.

Fragnet

A fragnet is the representation of a project network diagram that is often used for outsourced portions of a project, repetitive work within a project, or a subproject. Fragnet is also called a subnet.

Free Float

Free float is the total time a single activity can be delayed without it affecting the early start of its immediately followed successor activities.

Hard Logic

Hard logic describes activities that must happen in a particular order. For example, dirt must be excavated before the foundation can be built. The foundation must be in place before the framing can begin. Also known as a mandatory dependency.

Internal Dependencies

Internal relationships to the project or the organization. For example, the project team must create the software as part of the project’s deliverable before the software can be tested for quality control.

Lag Time

Lag time is a positive time that moves two or more activities further apart.

Late Finish

The latest possible time a project activity could finish. Late finish is used in the backward pass procedure to discover the critical path and the project float.

Late Start

The latest time a project activity can begin. Late start is used in the backward pass procedure to discover the critical path and the project float.

Lead Time

Lead time is negative time that allows two or more activities to overlap where ordinarily these activities would be sequential.

Management Reserve

Management reserve is the percentage of the project duration to combat Parkinson’s Law. When project activities become late, their lateness is subtracted from the management reserve.

Mandatory Dependencies

Mandatory dependencies are the natural order of activities. For example, you can’t begin building your house until your foundation is in place. These relationships are called hard logic.

Planning Package

A planning package is a WBS entry located below a control account and above the work packages. The planning package signifies that there is more planning that needs to be completed for this specific deliverable.

Precedence Diagramming

Precedence diagramming is a network diagram that shows activities in nodes and the relationship between each activity. Predecessors come before the current activity, and successors come after the current activity. They are project calendars that identify when the project work will occur.

Project Float

Project float is the total time the project can be delayed without passing the customer-expected completion date.

Project Network Diagram

A project network diagram visualizes the flow of project activities and their relationships to other project activities.

Soft Logic

Soft logic activities don’t necessarily have to happen in a specific order. For example, in a house you could install the light fixtures, then the carpet, followed by the paint in the room. The project manager could use soft logic to change the order of the activities if desired.

Start-to-Finish

Start-to-finish is an activity relationship that requires an activity to start so that its successor can finish. This is the most unusual of all the activity relationship types.

Start-to-Start

Start-to-start is an activity relationship type that requires the current activity to start before its successor can start.

Subnet

A subnet is a representation of a project network diagram that is often used for outsourced portions of projects, repetitive work within a project, or a subproject. Also called a fragnet.

Template

A template is a previous project that can be adapted for the current project and forms that are pre-populated with organizational-specific information.

Total Float

Total float is the total time an activity can be delayed without delaying project completion.

Work Package

A work package is the smallest item in the work breakdown structure.