Key Definitions

Activity: An element of work performed during of a project. (Normally has duration, cost, and resource requirements.)

 

Baseline: The Project original plan which determine the earliest completion date.

 

Backward Pass: The calculation of late finish and start dates for the uncompleted portions of all network activities. Determined by working backwards through the network logic from the project's end date.

 

Crashing: Taking action to decrease the total project duration after analyzing a number of alternatives to determine how to get the maximum duration compression for the least cost.

 

Critical Activity: An activity on a critical path.

 

Critical Path: The critical path is usually defined as those activities with float

Less than or equal to a specified value (usually zero).

 

Critical Path Method (CPM): A network analysis technique used to predict project duration by analyzing which path has the least amount of scheduling flexibility. Early dates are calculated using a forward pass; late dates are calculated using a backwards pass.

 

Data Date (DD): The point in time that separates actual (Historical) data from future (Planned) data. Also called as-of date.

Duration (DU): The number of work periods (not including holidays and other non- working periods) required to complete an activity or other project element.

 

Early Finish Date (EF): In the critical path method, the earliest possible date in which the uncompleted portions of an activity or project can complete.

 

Early Start Date (ES): In the critical path method, the earliest possible date in which the uncompleted portions of an activity or project can start.

 

Effort: The number of labor units required to complete an activity or other project element.

 

Event-on-Node: A network diagramming technique in which events are represented by nodes connected by arrows to show the sequence in which the events are to occur.

 

Fast Tracking: Compressing the project schedule by overlapping activities that would normally be done in sequence.

 

Float: The amount of time that an activity may be delayed from its early start without delaying the project finish date. (Also called slack, total float).

Forward Pass: The calculation of the early start and early finish dates for the uncompleted portions of all network activities.

Free Float (FF): The amount of time an activity can be delayed without delaying the early start of any immediately succeeding activities.

Gantt chart: A graphic display of schedule-related information using bars.

Hammock: An aggregate or summary activity.

Hanger: An unintended break in a network path. Hangers are usually caused by missing activities or missing logical relationships.

Lag: A modification of a logical relationship which directs a delay in the successor task.

Late Finish Date (LF): In the critical path method, the latest possible date that an activity may be completed without delaying a specified milestone (usually the project finish date).

 

Late Start Date (SF): In the critical path method, the latest possible date that an activity may begin without delaying a specified milestone (usually the project finish date).

 

Lead: A modification of a logical relationship which allows an acceleration of the successor task (Also called Negative Lags). For example, in a FS relationship with a 10 day lead, the successor can start 10 days prior to the completion of the predecessor.

Logical Relationship: A dependency between two project activities or between an activity and a milestone. Four possible types: FS, FF, SS, and SF.

 

Master Schedule: A summary level schedule which identifies the major activities and milestones.

Milestone: A significant event in the project, usually completion of a major deliverable and consumes no resources or duration.

Milestone Schedule: A summary level schedule which identifies the major milestones.

Path Convergence: In mathematical analysis, the tendency of parallel paths of approximately equal duration to delay the completion of the milestone where they meet.

Precedence Diagram Method (PDM): A network diagramming technique in which activities are represented by nodes. Activities are linked by precedence relationships to show the sequence in which the activities are to be performed.

Program Evaluation and Review Technique (PERT): An event-oriented network analysis technique used to estimate project duration when there is a high degree of uncertainty with the individual activity duration estimates.

 

Project Network Diagram: Any schematic display of the logical relationships of project activities.

Always drawn from left to right to reflect project chronology. Often incorrectly referred to as a "PERT chart".

 

Remaining Duration (RDU): The time needed to complete an activity.

 

Resource Leveling: Any form of network analysis in which start and finish dates are driven by resource management concerns.

 

Resource-Limited Schedule: A project schedule whose start and finish dates reflect expected resource availability. The final project schedule should always be resource limited.

 

Scheduled Finish Date (SF): The point in time work was scheduled to finish on an activity. The scheduled finish date is normally within the range of dates delimited by the early finish date and the late finish date.

 

Scheduled Start Date (SS): The point in time work was scheduled to start on an activity.

The scheduled start date is normally within the range of dates delimited by the early start and late start dates.

 

Time-Scaled Network Diagram: Any project network diagram drawn is such a way that the positioning and length of the activity represents its duration. Essentially, it is a bar chart that includes network logic.