Activity network diagram

Activity network diagram is a control tool used to establish and observe the most adequate path, also known as the critical path, and also a pragmatic agenda for the finalization of a project. The diagram is displayed graphically, describing a brief picture of all assignments, their sequence, their predicted completion time and the activities that could be completed simultaneously (Basu R, 2004, p. 129).

An activity network diagram is often referred to as:

• Pert (project evaluation and review technique) in some alternations;
• Cpm (critical path method);
• a precedence diagram;
• network analysis

Application of the activity network diagram

In the 1960s and 1970s the activity network diagram was broadly implemented in most projects. The more complex larger projects got, comprising plentiful tasks, the faster its popularity by manual methods started to decline. However, with the arrival of software systems like Ms Project and Primavera, its application at the more advanced stages of the project has increased extremely (Basu R, 2004, p. 129).

Benefits of the activity network diagram

The activity network diagram provides couple of benefits to the table. Some of them are (Basu R, 2004, p. 129).

• The team members can envision seriousness of primary tasks in the overall realization of the project;
• It outlines the problems of bottlenecks and unrealistic schedules;
• It grants facilities a possibility to review and regulate both the resources and the timetables for explicit activities.

Methods of construction

To construct the activity network diagram the two methods are usually used. The activity on arrow method and the activity on node method. The most commonly used method is the latter one - activity on node. The stages of implementing the activity on arrow method described by Ron Basu as follows (Basu R, 2004, p. 129):

1. Assemble the project team with the ownership and knowledge of key tasks.
2. List the key tasks with brief description of each one.
3. Identify the first task that must be done. The tasks must be done in parallel and the sequential relationship between tasks.
4. Draw arrows for each task which are labelled between numbered nodes and estimate a realistic time for the completion of eash of these tasks.
5. Avoid feedback loops in the diagram. Unlike Gantt charts, the length of the arrows does not have any significance.
6. Determine the longest cumulative path as the critical path of the project.
7. Review the activity network diagram and adjust resources and schedules if appropriate.

Examples of Activity network diagram

• The most common example of an activity network diagram is the Gantt chart. It is a visual representation of project tasks and their interdependencies. This chart shows the task sequence, their start and end dates, and their estimated duration. It also shows the resources used to complete the tasks and their associated cost.
• Another example of an activity network diagram is the Program Evaluation and Review Technique (PERT). It is a graphical representation of the project timeline and its associated tasks. The PERT diagram shows the duration of each task, the sequence of tasks, and how long each task will take to complete. It also shows the critical path of the project, which is the shortest path through the network of tasks.
• The Critical Path Method (CPM) is another type of activity network diagram. It is used to determine the earliest completion time of a project by analyzing the sequence of tasks and their respective durations. The CPM diagram shows the expected duration for each task, the sequence of tasks, and how long each task will take to complete. It also shows the critical path of the project, which is the longest path through the network of tasks.

Limitations of Activity network diagram

Activity network diagrams are useful tools for project management, but they also have some limitations. These include:

• Complexity: Activity network diagrams can be difficult to create and understand. In order to create a comprehensive diagram, a deep understanding of project tasks, their order and dependencies is required. It can also be hard to visualize the impact of changes in the project timeline and plan.
• Cost: Creating an activity network diagram can be expensive as it requires a lot of time and resources.
• Limited Adaptability: Activity network diagrams are rigid and can be difficult to update if there are changes in the project timeline or scope.
• Human Error: Activity network diagrams can be prone to human error, as the diagram relies on accurate information from the users. If the information is incorrect, it can lead to inaccurate results.

Other approaches related to Activity network diagram

The following are other approaches used in conjunction with the Activity Network diagram to create a complete project management system.

• Gantt Charts: Gantt Charts provide a visual timeline for a project that can be used to track the progress of projects and identify any tasks that are behind schedule.
• Critical Path Method: The Critical Path Method (CPM) is a tool used to determine the total duration of a project. It identifies the longest path of activities that must be completed in order to finish the project on time.
• Earned Value Analysis: Earned Value Analysis (EVA) is used to measure the performance of a project by calculating the amount of budgeted resources that have been used to complete a project.
• Project Scheduling: Project scheduling is the process of creating a timeline for a project. This involves determining the start and end date of a project, allocating resources, and identifying any potential risks.
• Risk Management: Risk management is the process of identifying, assessing, and responding to potential risks that could have an impact on a project.

In summary, the Activity Network diagram is used to establish and observe the critical path and create a timeline for a project. Other approaches used in conjunction with the Activity Network diagram include Gantt Charts, Critical Path Method, Earned Value Analysis, Project Scheduling, and Risk Management. These approaches are used to create a complete project management system.

Activity network diagram — recommended articles

Critical path method — Project cost management — Baseline schedule — Arrow diagram — Earned value analysis — Critical activities — Software cost estimation — Network charts — Project risk assessment — Human resources development

References

• Basu R, (2004), Implementing quality: A practical guide to tools and techniques: Enabling the power of operational excellence, Thomson, Great Britain
• Rumane A.R, (2013), Quality tools for managing construction projects, Crc press Taylor&Francis group, Usa
• Rumane A.R, (2016), Handbook of construction management: Scope, schedule, and cost control, Crc press Taylor&Francis group, Usa
• Urdhwareshe H, (2011), Six sigma for business excellence: Approach, tools and applications, Pearson, India

Author: Jakub Winiarski