NETWORK DIAGRAMS ARE SCHEMATIC DISPLAYS OF PROJECT SCHEDULE ACTIVITIES AND THE INTERDEPENDENCIES BETWEEN THESE ACTIVITIES. WHEN DEVELOPED PROPERLY, THIS GRAPHICAL VIEW OF A PROJECT’S ACTIVITIES CONVEYS CRITICAL SCHEDULE CHARACTERISTICS REQUIRED TO EFFECTIVELY ANALYZE AND ADJUST SCHEDULES – THUS RESULTING IN ACCURATE AND FEASIBLE SCHEDULES. THIS DOCUMENT ADDRESSES WHAT SHOULD BE CONSIDERED IN THE DEVELOPMENT OF A NETWORK DIAGRAM, HOW NETWORK DIAGRAMS ARE CREATED, AND HOW THEY MAY BE ANALYZED TO IDENTIFY NECESSARY CORRECTIVE ACTIONS AND ENSURE OPTIMAL SCHEDULE DEFINITION.
Network Diagram Creation
Network diagrams can be created manually but are also available as project views in project scheduling tools such as Microsoft Project. (See Microsoft Project, View→ More Views → Network Diagram).
• Project Scope Statement – The schedule definition required in network diagram development must be based on the approved scope documented in the Project Scope Statement. If network diagram and schedule definition does not account for all required deliverables in scope, the resulting network diagram and schedule will not accurately reflect the time necessary to complete the work. • Work Breakdown Structure (WBS) – The Project Team must include WBS project work in the network diagram to ensure comprehensive reflection of project activities. • Historical Project Information – The accuracy of network diagram/schedule estimation is strengthened by actual schedule metrics from past projects. Project teams should consider past level of effort and duration for comparable project activities. • WBS Dictionary – The WBS Dictionary defines task durations, dependencies, predecessor and successor relationships, and resources – all of which need to be defined prior to network diagram creation to ensure that the network diagram accurately reflects the schedule required to successfully complete the project. • Resource Calendars – The Project Team should develop and utilize a resource calendar that includes holidays and personnel availability. Creation of this calendar prior to network diagram creation will ensure that the schedule accounts for actual working time.
• Consider all inputs and enter all activity definition, sequencing, and duration information into a software tool such as Microsoft Project. If using this tool, ensure all tasks are linked. • Confirm all tasks are linked with accurate dependencies and with resource names identified for each task.
• Microsoft Project Plan with task dependencies, predecessors and successors defined, and resources applied to tasks
Below is a sample network diagram. To illustrate the relationship between a Gantt chart and a Network Diagram, we have provided the Gantt of activities and the Network Diagram view.
[pic]Sample Gantt Chart
[pic]Correlating Network Diagram Page 1
Correlating Network Diagram Page 2
Schedule Network Analysis
Schedule network analysis, as defined by the Project Management Body of Knowledge (PMBOK), is a technique used by project managers to analyze schedule information and generate realistic and optimal project schedules. This analysis should be performed upon completion of the draft schedule and network diagram and after each schedule update. Schedule network analysis involves: • Identifying the schedule impact of task dependencies
• Identifying critical path tasks and understanding the impact of the critical path on the schedule. Software tools such as Microsoft Project automatically display critical path tasks once project information such as tasks, dependencies, and durations are identified in the tools. • Analyzing the effects of schedule constraints and externally imposed dates • Understanding which tasks can experience delays without delaying the overall schedule • Conducting “what if” analysis of various activity durations (for example, what if the...