Project Management Primer #3 - The Critical Path

Another important concept in planning projects is that of the critical path. If a project consists of a set of tasks which need to be completed, the critical path represents the minimum such set, the critical set.

This might seem to be a contradiction since you might think completion of all tasks is necessary to complete a project; after all, if they weren’t necessary they wouldn’t be part of your project, would they?

The critical path represents not the ideal set of tasks to be complete for your project, but the minimum set. It is this path that you must traverse in order to reach completion of your project on time. Other tasks while important to overall completion do not impact upon the final delivery for the project.

They can therefore be rescheduled if time is tight or circumstances change. Tasks on your critical path however will affect the delivery time of the project and therefore should only be modified in extremis.

In the following example the critical path is represented in bold. In order to complete my project of cooking breakfast I have to go through the steps of frying bacon and sausages and scrambling eggs.

The tasks “make toast” and “wash plates”, while important, are not time-dependent or as critical as the other three tasks. I can move either of those tasks but if I try to move anything on the critical path it’s going to delay the project.

Ideally I’d like to have toast with my breakfast but a) it’s not essential and b) it doesn’t matter where in the process it happens. If I make toast before or after scrambling my bacon, it makes little difference to the overall result.

On the other hand I can hardly fry my bacon before the oil is hot; nor can I scramble my eggs before frying my bacon (they’d turn to glue).

The critical path represents the critical sequence of events which must occur if I want to successfully complete my project.

Normally major 'milestones' will be represented on the critical path and they will often occur when different threads of the project come together.

For example in the diagram to the right my only milestone is when I serve the completed breakfast. At this point I will have finished my preparations and completed everything on both tracks. This is represented by a diamond in the diagram above.

If I suddenly discovered I was late for work, I could cheerfully discard the optional “toast” component of my project, take the critical path instead and still achieve my original milestone of delivering breakfast (and maybe even make it to work on time!).

More Tutorials:

• 10 Truths for Successful Project Management

• Scope Triangle

• Critical Path

• The Mythical Man Month

• Defining the Project Scope

• Scope, Visions and Goals

• Using Project Goals to Filter Requirements

• Difference between a Business Case and Project Proposal?

• Return on Investment

• Requirements Specifications

Other Project Management Templates

Here are some Project Management templates you can get on our partner's site.

	The Change Management Kit provides the documentation required to control changes to the scope, deliverables and resources within the project. The Change Request template allows staff to raise a change request within the project.
	The Project Planning Kit provides you with all of the project management templates, documents and forms required to plan a project by helping you to schedule time, cost and resources.
	The Quality Management Kit includes a suite of templates used to assure and control the quality of deliverables within a project.
	Project Initiation Kit Start a new project by documenting a business case, undertaking a feasibility study, defining the project scope, recruiting key staff and locating them within a project office.
	Project Execution Kit Manage time, cost, quality, change, risks and issues during the execution of your project, as well as supplier procurement and customer acceptance.
	Project Closure Kit Helps close your project by handing over deliverables and documentation to the customer, terminating supplier contracts and releasing resources back to the business.