Model Answer
0 min readIntroduction
Project management relies heavily on effective planning and scheduling to ensure timely completion within budget. A precedence diagram, also known as an activity-on-node (AON) network diagram, is a visual representation of project tasks and their dependencies. It illustrates the sequential relationships between activities, identifying which tasks must be completed before others can begin. This technique is crucial for identifying the critical path – the longest sequence of activities that determines the shortest possible project duration. Without a specified process, we will construct a precedence diagram for a simplified software development lifecycle.
Understanding Precedence Diagrams
A precedence diagram uses nodes to represent activities and arrows to show dependencies. There are four types of dependencies:
- Finish-to-Start (FS): Activity B cannot start until Activity A is finished. (Most common)
- Start-to-Start (SS): Activity B cannot start until Activity A has started.
- Finish-to-Finish (FF): Activity B cannot finish until Activity A is finished.
- Start-to-Finish (SF): Activity B cannot finish until Activity A has started. (Rarely used)
Software Development Lifecycle – Example Process
Let's consider a simplified software development lifecycle with the following activities:
- A: Requirements Gathering
- B: System Design
- C: Database Design
- D: Coding
- E: Testing
- F: Deployment
Precedence Diagram Construction
The following dependencies exist:
- B depends on A (FS)
- C depends on A (FS)
- D depends on B and C (FS) – both must be completed
- E depends on D (FS)
- F depends on E (FS)
Visual Representation (Precedence Diagram)
Due to the limitations of text-based responses, a visual diagram cannot be directly rendered. However, the diagram can be described and its structure outlined. Imagine a network diagram where:
- Each activity (A-F) is represented by a box (node).
- Arrows connect the boxes, indicating dependencies.
The diagram would look like this (described):
- A (Requirements Gathering) is the starting point.
- Arrows lead from A to both B (System Design) and C (Database Design).
- Arrows lead from both B and C to D (Coding).
- An arrow leads from D to E (Testing).
- An arrow leads from E to F (Deployment).
Critical Path Analysis (Simplified)
In this example, the critical path is likely A -> B -> D -> E -> F. This is because any delay in these activities will directly delay the project completion. The critical path is determined by summing the duration of each activity along each possible path and identifying the longest path.
Table Summarizing Activities and Dependencies
| Activity | Predecessors | Dependency Type |
|---|---|---|
| A (Requirements Gathering) | None | - |
| B (System Design) | A | FS |
| C (Database Design) | A | FS |
| D (Coding) | B, C | FS |
| E (Testing) | D | FS |
| F (Deployment) | E | FS |
Conclusion
Constructing a precedence diagram is a vital step in project planning. It provides a clear visual representation of task dependencies, enabling effective scheduling and resource allocation. Identifying the critical path allows project managers to focus on activities that directly impact project completion time. While this example used a simplified software development lifecycle, the principles apply to a wide range of projects, enhancing project success rates and minimizing potential delays.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.