Network Analysis

Network analysis is a project management technique used to plan and control complex projects. It is often linked to Critical Path Analysis, or CPA. The technique helps managers break a project into separate activities, estimate how long each activity will take and identify which activities depend on others being completed first.

A network diagram shows the order in which activities must happen. For example, a business may need to complete a site survey before construction work begins, or install equipment before staff training can take place. This makes network analysis useful for projects where timing, sequencing and resource planning are important.

Activities are the tasks that make up the project. Each activity has a duration, such as three days, two weeks or four months. The diagram also shows dependencies. A dependency exists when one activity cannot start until another activity has been completed.

Nodes are points in the network where activities start or finish. Some network diagrams also use dummy activities. These do not take time, but they show a dependency clearly where one activity must wait for another before continuing.

A key aim of network analysis is to identify the critical path. The critical path is the longest sequence of dependent activities through the project. It determines the minimum time needed to complete the whole project. If any activity on the critical path is delayed, the whole project will be delayed unless managers take corrective action.

Network analysis also uses Earliest Start Time, or EST, and Latest Finish Time, or LFT. EST shows the earliest point at which an activity can begin. LFT shows the latest point at which an activity can finish without delaying the whole project.

Float is another important part of network analysis. Float shows how long an activity can be delayed without delaying the completion of the project. Total float is commonly calculated using the formula: Latest Finish Time minus activity duration minus Earliest Start Time. Activities with no float are usually on the critical path.

Free float may also be used in some specifications. Free float shows how long an activity can be delayed without delaying the start of the next activity. This can be useful where managers need to understand whether a delay affects the next stage of the project, even if it does not delay the whole project.

Network analysis can help managers plan resources. If they know which activities are critical, they can prioritise labour, equipment, materials or contractors for those activities. Activities with float may allow managers to move resources elsewhere without delaying the overall project.

CPA can also improve monitoring. Managers can compare actual progress with the planned network and identify where delays are most serious. This is useful in construction, product launches, store openings, IT upgrades, events and other time-sensitive projects.

However, network analysis has limitations. It depends on accurate estimates of activity durations and dependencies. If managers underestimate how long tasks will take, the network may give a false sense of certainty. Unexpected problems, supplier delays, staff shortages or weather disruption may make the original plan less reliable.

CPA can also focus attention on time rather than quality, cost or flexibility. Completing a project quickly is not always the same as completing it well. A business may need to balance speed against safety, quality, customer experience and budget control.

Overall, network analysis is useful when a project has clear activities, timings and dependencies. It is most valuable when managers use it to guide decisions, monitor progress and respond to delays, rather than treating the diagram as a guaranteed prediction.