Activity Network Diagram

An Activity Network Diagram (AND) is also called an Arrow Diagram (because the pictorial display has arrows in it) or a PERT (Program Evaluation Review Technique) Diagram, and it is used for identifying time sequences of events which are pivotal to objectives. In Critical Path Analysis this helps the teams to comprehend specific event sequences driving time requirements for objective achievement. Activity Network Diagrams are also very useful when a project has multiple activities which need simultaneous management.

Activity Network Diagrams started out as an engineering and construction project management tool. Critical Path Analysis draws on this methodology to identify and standardize medical management activities.

An Activity Network Diagram helps to find out the most efficient sequence of events needed to complete any project. It enables you to create a realistic project schedule by graphically showing

• the total amount of time needed to complete the project
• the sequence in which tasks must be carried out
• which tasks can be carried out at the same time
• which are the critical tasks that you need to keep an eye on.

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Example of Activity Network Diagram

A project is composed of a set of actions or tasks which usually have some kind of interdependency. For example, before an axle can be turned, it must first be designed, the metal must be purchased, etc. This type of complex system is much easier to understand through the use of diagrams than through textual description, as actual interconnections between tasks can be shown. You can draw the activity network diagram easily with Edraw software.

The Activity Network diagram displays interdependencies between tasks through the use of boxes and arrows. Arrows pointing into a task box come from its predecessor tasks, which must be completed before the task can start. Arrows pointing out of a task box go to its successor tasks, which cannot start until at least this task is complete.

Activity Network Diagram Drawing Rule

All the preceding activities must be completed before the project can begin.

The arrows represent the logical precedence of the project.

History of Activity Network Diagram

It was developed by the U.S. Department of Defense. It was first used as a management tool for military projects. It was Adapted as an educational tool for business managers.

UML Activity Diagram