Dependency Determination
Dependency Determination is the process of identifying and documenting the logical, mandatory, external, and discretionary relationships between project activities. Recognizing these dependencies is crucial for accurate sequencing of activities and for developing a realistic project schedule. Dependencies can influence the project's timeline and must be carefully considered during the planning phase. There are four main types of dependencies: 1. **Mandatory Dependencies (Hard Logic):** These are inherent in the nature of the work and often involve physical limitations. For example, you cannot install wiring until the building framework is complete. 2. **Discretionary Dependencies (Soft Logic):** These are defined by the project team based on best practices or project preferences. They offer flexibility and can be adjusted if necessary. An example is choosing to complete design approval before initiating procurement. 3. **External Dependencies:** These involve relationships between project activities and non-project activities, often outside the project team's control. For instance, obtaining permits from government agencies before construction can begin. 4. **Internal Dependencies:** These are within the project's control and involve precedence relationships between project activities. For example, the project team may need to complete a training session before starting a particular task. Understanding dependency determination allows project managers to sequence activities logically, anticipate potential delays, and allocate resources efficiently. It also aids in risk management by identifying areas where dependencies could impact the schedule due to uncertainties or external factors. Proper documentation of dependencies ensures clarity and aids in communication among stakeholders, facilitating smoother project execution.
PMI-SP: Dependency Determination - Complete Guide
What is Dependency Determination?
Dependency determination is a critical scheduling technique that identifies and documents the logical relationships between project activities. These relationships, known as dependencies, dictate the sequence in which activities must be performed.
Why is Dependency Determination Important?
Dependency determination forms the backbone of schedule development in project management. It:
- Creates a logical framework for project execution
- Determines the critical path of the project
- Allows for accurate calculation of project duration
- Helps identify schedule constraints and opportunities
- Facilitates resource allocation and risk management
Types of Dependencies
1. Mandatory Dependencies (Hard Logic)
- Physical limitations that cannot be changed
- Example: You cannot install software until hardware is assembled
2. Discretionary Dependencies (Soft Logic)
- Based on best practices or preferred sequences
- Example: Painting interior walls before installing carpet
3. External Dependencies
- Relationships between project and non-project activities
- Example: Waiting for regulatory approval before proceeding
4. Internal Dependencies
- Relationships between project activities under the team's control
- Example: One team must complete their work before another can start
Dependency Relationships (Network Diagrams)
Most scheduling uses the Precedence Diagramming Method (PDM) with these relationships:
1. Finish-to-Start (FS)
- Most common type
- Successor cannot start until predecessor finishes
- Example: Foundation must be complete before framing begins
2. Start-to-Start (SS)
- Successor cannot start until predecessor starts
- Example: Editing can begin once writing has started
3. Finish-to-Finish (FF)
- Successor cannot finish until predecessor finishes
- Example: System testing cannot finish until defect fixing is complete
4. Start-to-Finish (SF)
- Successor cannot finish until predecessor starts
- Rarely used
- Example: New system must start before old system can be shut down
Lead and Lag Time
Lead Time: Acceleration of successor activity
- Example: FS-5 days means successor can start 5 days before predecessor finishes
Lag Time: Delay in successor activity
- Example: FS+10 days means successor starts 10 days after predecessor finishes
Process of Dependency Determination
1. Identify all project activities
2. Analyze activities to identify logical relationships
3. Document dependencies using network diagrams
4. Validate dependencies with experts and stakeholders
5. Incorporate dependencies into the project schedule
6. Monitor and update as the project progresses
Dependency Determination Tools
- Precedence Diagramming Method (PDM)
- Schedule network templates
- Project management software
- Expert judgment and historical information
- Dependency determination workshops
Exam Tips: Answering Questions on Dependency Determination
1. Know the dependency types thoroughly - Be able to distinguish between mandatory, discretionary, external, and internal dependencies.
2. Understand relationship types - Be comfortable identifying FS, SS, FF, and SF relationships and when each is appropriate.
3. Calculate with lead and lag - Practice working with lead and lag times in schedule calculations.
4. Focus on sequencing logic - Questions often ask which activities must come before others.
5. Identify missing dependencies - Look for logical gaps in sequence scenarios.
6. Recognize impact on critical path - Understand how dependencies affect the critical path and project duration.
7. Connect to other knowledge areas - Be aware of how dependencies relate to risk, resources, and project constraints.
8. Apply situational judgment - Some questions may ask what dependency type is most appropriate in a given scenario.
9. Watch for optimization opportunities - Questions may ask how to improve a schedule by adjusting dependencies.
10. Remember the purpose - Dependencies exist to create a logical, efficient, and realistic project schedule.
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