Year 13
Business Strategy
Network or Critical Path analysis
This is a technique which allows a business to:
Í Estimate the minimum time that could be taken to complete a possibly complex operation.
Í Identify whether resources are being used efficiently
Í Anticipate a y tasks that may or may not cause delays in the operation
Critical path analysis is used in many industries, particularly manufacturing and construction.
A simple operation – such as painting a window frame, which a builder might carry out. This could involve many different tasks e.g.
Ø Preparing the woodwork
Ø Appling the undercoat
Ø Waiting for the undercoat to dry
Ø Applying the gloss
There are certain features that are important when constructing networks.
The circles are called nodes. They show the start/finish of the tasks.
For example waiting for paint to dry uses resources, such as time. Activities are dependent on each other.
Nodes contain information, nodes are divided into 3 sections, the left hand section of the node has the node number in it. The right hand section is split into two, with earliest start time at the top and latest finishing time at the bottom. This shows the latest time that the previous task can finish without delaying the next task.
The arrows show the order in which the task takes place. They often have letters next to them to show what the order is and the length of time each task takes is placed below the arrow.
Constructing a Network
In practice operations in business may be more complex with many different tasks. Some of which can be carried out at the same time as others e.g. the tasks involved in producing an advertising campaign for a company could be:
Ø A plan the advertising campaign
Ø B make a TV video
Ø C make a poster
Ø D test market the TV video
Ø E Test suitability of poster
Ø F present campaign to the board of directors
Ø G communicate the campaign to all company persons
The estimated length of time for each task and the order i.e. the tasks that depend upon others being completed are shown in the table below. The total estimated time is for 49 hours but that is not important as activities B, C, D, E can be done at the same time b different employees.
The table below shows the network for the marketing campaign, the tasks, node numbers, and time durations are all included.
Tasks Order/Dependency Estimated time/hours
A must be done first 4
B can only start when A is done 6
C can only start when A is done 7
D can only start when B is done 8
E can only start when C is done 10
F can only start when D/E are complete 9
G must wait for D, E and F to be complete 5
Construct the network in the space below
Once the network has been constructed it is possible to fill in the earliest start time and the latest finishing time, and then show the critical path.
This will tell the business how long it will take to launce the advertising campaign and indicate where delay could take place.
On the following page reconstruct the network and input the earliest start times and latest finishing times following the instructions given.
Advertising campaign network
The earliest start time assuming that the estimated time task A can start is hour 0 then tasks B and c cannot start for 4 hours. 0+4 until task A has been completed. These should be shown in the top right of nodes 1 and two.
Task D cannot start until A and B have been completed, this takes 10 hours 0+4+6 which is shown in node 3.
Task E can’t start for 11 hours = 0+4+7 shown in node 4.
Task F can’t start until E and D are complete The EST for F is 21 hours = 0+4+7+10. Always choose the longest route for calculating the EST.
The route ABD is only 18 hours but show 21 which is the longer route.
Final node shows time it takes to complete whole marketing campaign = 35 hours. = 0+4+7+10+9+5 shown in node 7.
Node 6 is 9 +21 = 30
S.Matharu
Network or Critical Path analysis