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Critical path analysis


We often hear in the media about large projects running late. If you think about it, this must mean there was a plan or target. You can only be late if you have a plan or a target.

Businesses need to schedule projects to ensure the optimum use of scarce resources. This is especially important if the project involves the use of external contractors and equipment.

CPA or critical path analysis helps plan complex projects to ensure the best use of machinery, people and materials. One very good method is CPA. CPA is also known as PERT (Project Evaluation and Review Technique), network planning or networking.

Critical path analysis is a method of modelling a project so that:

  • Its logical route to completion can be established.
  • The key or CRITICAL jobs (ACTIVITIES) can be identified.
  • The time to complete the project can be estimated.
  • The progress of the project to completion can be effectively managed, and remedial work can be planned as necessary.

This is done by preparing a fully timed NETWORK DIAGRAM.

The use of networks can be expanded to the evaluation and control of all project resources, such as materials, plant, skilled and unskilled labour, as well as capital expenditure and cash flow.

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Critical Path Analysis (CPA)

CPA is a network planning technique used particularly in project management to identify the activities within a project that are critical for its success. A critical path is identified from a project diagram or flow chart, showing the sequence in which activities must be completed to minimise the duration and cost of the project.

There is some confusion, not to say competition, over its invention or birth. CPA was probably invented in the 1940s or 1950s by major US and British companies at approximately the same time. It was definitely used by the US Government to control the development of the Polaris submarine system and by Boeing for the introduction of the 747 'Jumbo jet'.

We will now jump in at the deep end. CPA is one of those techniques, like riding a bicycle, where it is best to try and do it, rather than talk about it! Firstly, we need to examine some basics about the planning process.