Schedule Network Analysis Methods

Project Schedule Network Analysis
Project Schedule Network Analysis

A project consists of various disciplines. Each discipline has its unique set of activities. Execution of these activities leads to fulfilment of a project goals. Project schedule network analysis brings all project activities on a single platform. As a result of which project work can progress unhindered. Further, project schedule network analysis helps to identify logically related project activities that need maximum attention of the project team. Moreover, project schedule network analysis also optimizes deployment of resources to meet project goals. This further helps in better realization of project goals and increase in efficiency.

What is Schedule Network Analysis?

Project schedule network analysis is an analytical technique to identify critical path and list of critical project activities. It further specifies the degree of schedule flexibility in a given network logic. The output of schedule network analysis is a schedule model. This project schedule model serves as a basis for further project execution, analysis, and reporting. Critical Path Method (CPM) is the most common schedule network analysis technique.

Advantages of Schedule Network Analysis?

The Schedule network analysis allows all stakeholders are aware of activities that define project success. It is an essential project management tool that finds application in not only schedule development but also schedule control process.

Following are some of the advantages of performing project schedule network analysis

  1. Sequence of Activities: Schedule network analysis specifies the logical sequence of activities required to achieve project goals. It uses sequencing and dependencies to establish activity relationships.
  2. Critical Path: Schedule network analysis uses techniques like CPM and PERT to identify the critical path of a project. The critical path is the longest path of a schedule network diagram. Refer to paragraph “Critical Path Method (CPM) Scheduling” to understand other features of critical path.
  3. Project Duration: It analytically estimates the minimum duration before which the project cannot complete.
  4. Critical Activities: Not all activities can start and finish at the same time. Activities on critical path are critical activities. Hence schedule network analysis indicates exactly which activities need maximum attention of project team.
  5. Schedule flexibility: Schedule network analysis also indicates permissible delay in activities not on critical path. It uses mathematical calculations to establish early start, early finish, late start, and late finish of each activity.
  6. Schedule Model: The output of project network analysis is the schedule model. It helps to conduct risk and scenario analysis of project schedule.
  7. Schedule Analysis: The schedule model allows further analysis like What-if analysis, scenario analysis and schedule compression techniques.

Relationships Between Schedule Activities

Establishing logical relationship among schedule activities is the process of knowing which activity comes first and which activity follows it. In other words, it helps to know predecessor and successor activities.

Schedule network analysis uses task dependencies to establish relationship between schedule activities. These dependencies are namely Finish-to-start (FS), Start-to-start (SS), Finish-to-finish (FF), Start-to-finish (SF) and lead and lags. Activity characteristics like mandatory, discretionary, internal and external relationships further assist in determining dependencies.

Understanding relationships among activities allows construction of schedule network diagram. The following post helps to understand how to establish relationships between project activities.

Types of Network Diagrams in Project Management

An important benefit of using schedule network analysis is that it allows visual representation of the project schedule. To achieve this it uses network diagramming techniques. The following two techniques help in constructing project schedule network diagram:

  • Precedence Diagram Method (PDM)
  • Arrow Diagram Method (ADM)

Precedence Diagram Method (PDM)

In PDM technique nodes represent the schedule activities. A graphical link between the nodes establishes logical relationships. The links also shows the sequence of performing the schedule activities.

Activity-On-Node (AON) is one such method of representing the schedule network logic using the PDM technique. Critical Path Method (CPM) uses AON method for constructing the project schedule network diagram.

The diagram below represents a typical project schedule network diagram with critical path and total float.

Project Schedule Network Diagram With Critical Path & Total Float
Project Schedule Network Diagram With Critical Path & Total Float

Arrow Diagram Method (ADM)

In Activity-On-Arrow (AOA) method arrows represent the schedule activities. AOA is an example of constructing the project schedule network diagram using ADM technique. Program Evaluation and Review Technique (PERT) analysis uses AOA technique for constructing the project schedule network diagram.

Precedence Diagram Method (PDM) Nomenclature

The following figure indicates the pmbok nomenclature for precedence diagram method.

Precedence Diagramming Method (PDM) - Nomenclature of Activity Node
Precedence Diagramming Method (PDM) – Nomenclature of Activity Node

Project Schedule Network Analysis Methods

Following are the two most popular schedule network analysis techniques.

  • Program Review and Evaluation Technique (PERT)
  • Critical Path Method (CPM)

United States Navy and  Booz Allen Hamilton developed PERT in 1957 to cater for defence projects. At about the same time, Morgan R. Walker of DuPont and James E. Kelley Jr. of Remington Rand developed CPM. Out of the two, the most widely used project schedule network analysis technique is the Critical Path Method (CPM).

Following are the other methods of schedule network analysis

  • Critical Chain Method (CCM)
  • What-if Analysis
  • Resource Optimization Techniques

Key Differences Between PERT & CPM

Critical Path Method (CPM) finds application in construction projects whereas PERT for research and development projects. PERT mainly controls time element of projects. PERT uses probabilistic time estimates to aid in determining the probability of project completion date.

Critical Path Method (CPM) on the other hand used deterministic activity time estimates. However, CPM can control both time and cost aspect of the project. Moreover, the modern-day scheduling software also provide PERT analysis of schedule developed using Critical Path Method (CPM).

Critical Path Method (CPM) Scheduling

Critical path method (CPM) is the most common schedule network analysis methodology. CPM establishes the critical path of a schedule network diagram. CPM analysis also calculates early start, early finish, late start and late finish with ease. The following snapshot enumerates critical path characteristics.

Schedule Network Analysis Critical Path Characteristics
Critical Path Characteristics

Refer to the following post to understand theory of critical path method (CPM) analysis.

Schedule Network Analysis Solved Example

Solving problems further simplifies the learning process and enhances the understanding of basic concepts. Following post enumerates steps in schedule network analysis process using the critical path method technique.

For schedule development process, you may please read the following post.

Conclusion

To summarize, project schedule network analysis is an essential project scheduling and controlling tool. As a matter of fact, critical path method (CPM) is the most common schedule network analysis technique. The output of project schedule analysis is a project schedule model. Further, a project schedule model has essential information like critical path, list of critical activities and the total float. Moreover, schedule model is an input for further modeling techniques such as what-if analysis and simulation. I hope this post serves as a resource for understanding critical path method (cpm) analysis technique.

For formulas used in critical path method (cpm) analysis, you may visit PMP Formulas under Resources page.

If you wish to get in touch with the author, you may visit the Contact page.

Author’s Profile

About Competencies Experience Resume Gallery