Comprehensive Glossary of CPM & P6 Scheduling Terms

A detailed reference of key scheduling terms for project management professionals using CPM and Primavera P6, including .xer file handling and delay analysis concepts.

General Terms

• Activity: A task or set of tasks required to complete a project.
• Activity Code: Labels used to sort, filter, and organize schedule activities.
• Milestone: A significant point or event in the project timeline with zero duration.
• Work Breakdown Structure (WBS): Hierarchical decomposition of project scope into manageable components.

Schedule Structure

• Baseline: The original approved project schedule, used as a reference for tracking progress.
• Baseline Schedule: The approved project schedule frozen for tracking changes over time.
• Baseline Type: Classification of baseline versions (e.g., primary, secondary).
• Calendar: Defines working and non-working time periods for the project and resources.
• Data Date: The current date being used for schedule updates and progress reporting.
• Time-Scaled Logic Diagram: Network diagram showing activities on a time scale.

Scheduling Concepts

• Concurrent Activities: Two or more activities scheduled to occur simultaneously.
• Critical Path: The longest sequence of tasks determining the shortest time to complete a project.
• Duration, Actual: The elapsed time from when an activity started to when it finished, measured in working days.
• Duration, Original: The estimated number of working days required to complete an activity, excluding holidays. This duration is determined by the assigned activity calendar.
• Duration, Remaining: The number of working days needed to complete an activity as of the data date.
• Early Start/Finish: Earliest dates an activity can begin/end based on network logic.
• Float, Free (FF): Time an activity can be delayed without affecting successor activities.
• Float, Total (TF): Time an activity can be delayed without extending the project completion date.
• Gantt Chart: A bar chart used to visualize a project schedule. Each bar represents an activity, with its length proportional to the activity's duration. Often includes dependencies between activities.
• Late Start/Finish: Latest dates an activity can begin/end without delaying the project.

Schedule Compression

• Crashing: Adding resources to compress the schedule duration at minimal cost increase.
• Fast Track: Scheduling technique where activities are performed in parallel rather than sequentially to compress duration.
• Schedule Compression: Techniques to reduce project duration without changing scope (e.g., crashing, fast tracking).

Resource Management

• Cost Loading: Assigning costs to schedule activities to create time-phased budgets.
• Resource Loading: Assigning labor, equipment, and materials to schedule activities.
• Resource Optimization: Adjusting resource allocations to avoid conflicts or overallocations.

Dependencies and Relationships

• Dependencies: Logical relationships between activities, such as finish-to-start or start-to-start links.
• Lead: An overlap where a successor activity starts before its predecessor finishes.
• Lag: A delay applied to a dependency between two activities.
• Predecessor: An activity that must be completed before another activity can begin.
• Successor: An activity that follows and depends on the completion of another activity.

Risk and Analysis

• Buffer/Contingency: Reserved time added to activities or the overall schedule to account for uncertainty and risk.
• Half-Step or Bifurcation Schedule Analysis: A technique that separates the effects of schedule changes and activity progress.
• Out-of-Sequence Progress: Work performed in a different order than planned logic.
• Progress Override: Schedule calculation option for handling out-of-sequence work.
• Retained Logic: Schedule calculation option maintaining planned activity sequences.
• Schedule Network Analysis: Techniques to identify early dates, late dates, and float using forward and backward pass calculations.
• Schedule Risk Analysis: Monte Carlo simulation to assess schedule uncertainty.
• Variance Analysis: The process of comparing planned performance to actual performance to identify deviations.

Support Activities

• Level of Effort (LOE): Support activities, like project management, that continue for the project duration.

Visualization Tools

• Gantt Chart: A bar chart used to visualize a project schedule. Each bar represents an activity, with its length proportional to the activity's duration. Often includes dependencies between activities.