Once the Project Network Diagram has been created, it can be tranformed into a working activity diagram by adding useful information to each activity box.
Each activity box should contain:
- A unique identification number for each activity (no two activities can have the same number on the same project).
- A clear activity description which would aid in identifying the predecessors and successors to the activity.
- Duration estimate (illustrated in the diagram).
On large projects it is a good idea to include the activity WBS and or OBS codes in order to clearly group and identify activity relationships.
If there is enough room in the boxes, then other type of information can be included, but only if it helps in the network building process, such as project cost. However, the more information you include (other than the minimum items listed above), the more variables you need to deal with and the more difficult it becomes to build one.
Once the project network is built , it follows logically to calculate the start and finish dates of each activity based on the following:
- The start date of the project (the start of the first activity).
- The duration of each activity.
- The logical sequencing of the activities as drawn in the network diagram.
The groups of activities that make up the longest path and therefore produce the projects' end date are known in the project management industry as the “Critical Path Activities”. Activities that are not on the critical path will have slack or float.