Network analysis, also known as critical path analysis, is a project management tool used to plan, monitor and control complex business projects.
What is Network Analysis?
Network analysis is a planning and scheduling technique used in project management to break down complex projects into a series of interconnected tasks. It provides a systematic method to outline all necessary activities, identify the relationships between them, and calculate the minimum time needed to complete the entire project. This approach allows businesses to organise, visualise, and coordinate activities in a way that promotes timely and effective strategic implementation.
Also referred to as Critical Path Analysis (CPA), network analysis highlights the sequence of dependent tasks and identifies those that are most time-sensitive. It allows managers to allocate resources efficiently and manage potential delays that might hinder strategic goals.
Strategic implementation often involves multiple departments, individuals, and tasks that must be coordinated precisely. Network analysis is used to ensure these activities are scheduled in the most efficient sequence to meet deadlines, avoid conflicts, and maximise productivity.
How Network Analysis Supports Strategy Execution
Effective strategic implementation depends not just on planning, but on ensuring that the plan is executed on time, within scope, and with coordinated efforts. Network analysis supports this in several ways:
Improves planning accuracy: By identifying task durations, dependencies, and sequencing, it provides a more accurate picture of the project timeline.
Clarifies task priorities: It helps identify which activities are critical (i.e. cannot be delayed) and which have float (i.e. can be delayed without impacting the overall project).
Allocates resources efficiently: By knowing which tasks are on the critical path, managers can focus labour, budget, and equipment accordingly.
Enhances communication: Visual diagrams provide clarity for teams, making it easier to communicate roles, deadlines, and potential bottlenecks.
Reduces risks of delays: By proactively planning for dependencies and task durations, businesses can reduce the chance of late project delivery.
For businesses implementing strategic change—such as launching a new product, entering a new market, or restructuring internal processes—network analysis provides the framework to manage complexity and achieve results effectively.
Key Components of a Network Diagram
Network diagrams visually represent the sequence, duration, and interdependence of tasks in a project. The four key components of a network diagram are:
Activities
An activity is a task or operation that needs to be performed.
Each activity has a specific duration and often requires resources (people, time, money).
Activities are often labelled with letters or numbers (e.g. Activity A, B, C).
Activities do not occur at a single point in time—they take time to complete.
For example, “Design marketing material” may be an activity with a duration of 4 days.
Nodes (Events)
A node represents a specific point in time, such as the start or completion of an activity.
In Activity-on-Arrow (AOA) diagrams, nodes are circles representing events, while arrows show the activities.
In Activity-on-Node (AON) diagrams, the nodes themselves contain the activity, and arrows indicate dependencies.
For AQA A-Level Business, AOA diagrams are commonly used, where arrows represent activities, and nodes represent events (start or end points).
Dependencies
Dependencies show the order in which tasks must be completed.
A task may depend on the completion of one or more previous tasks.
There are different types of dependencies:
Finish-to-start: Task B cannot start until Task A finishes (most common).
Start-to-start: Task B cannot start until Task A starts.
Finish-to-finish: Task B cannot finish until Task A finishes.
Understanding dependencies is crucial to ensure activities are not scheduled out of order, which could delay the project.
Duration
Duration is the estimated time it will take to complete an activity.
Typically measured in days, but could also be weeks or hours depending on the project.
Accurately estimating duration is vital because it influences the total project time and the calculation of critical paths.
Drawing a Simple Network Diagram Step-by-Step
To understand how network diagrams work, it's important to learn how to create one. The process involves several steps:
Step 1: List All Activities with Durations and Dependencies
Before drawing the diagram, create a list of all required activities. Include:
The name or label of each activity.
The duration of each activity.
Predecessor activities, i.e. tasks that must be completed before the current one can begin.
Example:
Activity A: 3 days (no dependencies)
Activity B: 4 days (depends on A)
Activity C: 2 days (depends on A)
Activity D: 5 days (depends on B and C)
This list helps you determine the structure of the diagram and the flow of work.
Step 2: Draw the Network Diagram
Using the above information, begin to draw:
A start node (often numbered 1).
Arrows for each activity leading from one node to another.
Each arrow is labelled with the activity name and duration.
For each dependency, ensure that activities begin after the previous ones finish.
In our example:
Node 1 to Node 2: Activity A (3 days)
Node 2 to Node 3: Activity B (4 days)
Node 2 to Node 4: Activity C (2 days)
Node 3 and Node 4 merge into Node 5: Activity D (5 days)
This creates two paths:
Path 1: A → B → D
Path 2: A → C → D
Step 3: Forward Pass – Calculate Earliest Times
The forward pass determines the earliest start (ES) and earliest finish (EF) times for each activity.
Formula:
Earliest Finish (EF) = Earliest Start (ES) + Duration
Start from the first node (usually ES = 0), and calculate EF for each activity. The ES for the next activity equals the EF of the preceding activity.
Example:
A: ES = 0, Duration = 3 → EF = 0 + 3 = 3
B: ES = 3 (from A), Duration = 4 → EF = 3 + 4 = 7
C: ES = 3 (from A), Duration = 2 → EF = 3 + 2 = 5
D: ES = 7 (must wait for both B and C, take later EF) → EF = 7 + 5 = 12
Total project duration: 12 days
Step 4: Backward Pass – Calculate Latest Times
The backward pass finds the latest start (LS) and latest finish (LF) times for each activity without delaying the project.
Formula:
Latest Start (LS) = Latest Finish (LF) - Duration
Start from the end of the project (EF of the last task = LF), then move backward.
Example:
D: LF = 12, Duration = 5 → LS = 12 - 5 = 7
B: LF = 7, Duration = 4 → LS = 7 - 4 = 3
C: LF = 7, Duration = 2 → LS = 7 - 2 = 5
A: LF = 3 (from B), Duration = 3 → LS = 3 - 3 = 0
Step 5: Calculate Float
Float (or slack) is the amount of time an activity can be delayed without delaying the project. Activities on the critical path have zero float.
Formula:
Total Float = Latest Start - Earliest Start
orTotal Float = Latest Finish - Earliest Finish
In our example:
A: ES = 0, LS = 0 → Float = 0
B: ES = 3, LS = 3 → Float = 0
D: ES = 7, LS = 7 → Float = 0
C: ES = 3, LS = 5 → Float = 2 (can be delayed by 2 days without affecting the total project)
Step 6: Identify the Critical Path
The critical path is the longest path through the network (in terms of duration), with no float. These activities must be completed on time.
In this example:
Path A → B → D = 3 + 4 + 5 = 12 days
Path A → C → D = 3 + 2 + 5 = 10 days
So, the critical path is: A → B → D
Delays in these activities would delay the entire project.
What is the Critical Path?
The critical path is a sequence of tasks that defines the minimum project completion time. It is made up of activities with zero float—they must start and finish as scheduled.
Key points:
Any delay on this path extends the total project duration.
Helps managers focus on high-priority tasks.
May shift if project parameters change.
There can be multiple critical paths if two or more sequences take the same maximum time.
Critical path analysis gives businesses an essential tool for risk management, prioritisation, and realistic deadline setting.
Summary of Key Terms and Equations
Earliest Finish (EF) = Earliest Start + Duration
Latest Start (LS) = Latest Finish - Duration
Total Float = LS - ES or LF - EF
Critical Path = Longest duration path with zero float
Understanding how to draw, read, and interpret network diagrams—and especially the critical path—is crucial for A-Level Business students aiming to master strategic implementation tools.
FAQ
Yes, it is possible for two or more paths in a network diagram to have the same duration, meaning there can be multiple critical paths. In this case, any delay in any of those paths will still delay the overall project. Having multiple critical paths increases the risk in project execution, as more tasks must be completed precisely on time. It also places more pressure on resource planning, since there are fewer opportunities to shift labour or capital between tasks.
Accurate duration estimates are essential because they form the basis for calculating the critical path and float. If a task’s duration is over- or underestimated, it can misrepresent which tasks are critical, lead to inefficient resource allocation, and result in missed deadlines. Inaccurate durations can also make it difficult to identify potential bottlenecks or delays in the project. Strategic implementation decisions rely heavily on accurate scheduling, so poor estimates can lead to costly strategic failure.
Network analysis maps out dependencies and highlights task durations, allowing managers to see where tasks converge or where several activities rely on a single resource. These points are potential bottlenecks—if delayed, they can disrupt multiple paths in the project. Identifying them early enables businesses to plan around them, allocate additional resources, or adjust timelines. This insight improves strategic implementation by reducing uncertainty and allowing pre-emptive actions to prevent delays or system overload.
Total float is the amount of time an activity can be delayed without delaying the overall project completion, whereas free float is the time an activity can be delayed without delaying the start of any subsequent activity. Free float is always equal to or less than total float. Understanding both types allows managers to optimise task sequencing and resource allocation more precisely, particularly when multiple tasks feed into a single dependent task or milestone.
While network analysis is traditionally used in project-based scenarios, it can be adapted for non-project-based strategic implementation, such as process changes or internal restructures. In such cases, activities can be mapped as stages in a broader strategic transition, with durations and dependencies defined based on functional shifts or team outputs. Though less precise than in formal projects, applying network analysis in this way can still improve visibility, coordination, and accountability across the organisation.
Practice Questions
Explain how identifying the critical path in a network diagram can support effective strategic implementation in a business. (10 marks)
Identifying the critical path allows managers to focus on tasks that must be completed on time to avoid project delays, making strategic implementation more efficient. By clearly highlighting the sequence of time-sensitive activities, businesses can allocate resources and staff more effectively, ensuring no time is wasted. It also enables early detection of potential bottlenecks and risks, helping managers plan contingencies. This visibility improves communication between departments and encourages accountability. Ultimately, using the critical path as a planning tool increases the likelihood of delivering the strategy within deadline and budget, which is essential for successful implementation.
Analyse how float time in network analysis can help a business manage resources during strategy implementation. (10 marks)
Float time represents the flexibility available in scheduling non-critical tasks without delaying the project. This can help a business manage resources more effectively by reallocating labour or capital from activities with float to those on the critical path. For instance, if one team finishes early, they can assist with critical tasks, improving efficiency. Float also offers room for unexpected delays in non-critical areas without compromising the overall timeline. This flexibility reduces the risk of project failure and supports smoother strategic implementation. By using float strategically, a business can better manage workload pressures and avoid unnecessary downtime.
