Creating a realistic schedule is a key responsibility of any project manager. This schedule must be updated regularly throughout the duration of the project to ensure that the project manager is aware of any issues or delays that might affect the product delivery date. Too many delays can lead to additional expense, customer dissatisfaction and project failure.

The Critical Path Method (CPM) is a widely-used technique developed by project managers to enable close analysis of the factors affecting the project schedule. Through Critical Path Analysis (CPA), project managers are able to make more accurate schedules and estimations.

The popular project management software, MS Project, includes various tools to facilitate creating and managing a Critical Path. This article considers how MS Project can make developing and using a Critical Path a simple, step-by-step procedure.

Creating a Critical Path using MS Project

Microsoft Project allows users to create and manage a Critical Path using the Gantt Chart capability. A Gantt Chart represents the tasks necessary to complete a project. The MS Project Gantt Chart represents task dependencies (when one task cannot be started until another is complete), task duration (including ‘slack’ – the number of days a task can run over schedule) and also summary tasks (groups of subtasks). The MS Project Gantt Chart view is automatically displayed at the start of any project.

The Critical Path describes the shortest possible sequence of tasks that are essential to successful project closure. The tasks on a project’s Critical Path will be interdependent: that is, one task is a pre-requisite for carrying the next. When the last task on the Critical Path is complete, the project can close. Any task that is not necessary for carrying out another task, or for project closure, is not part of the Critical Path.

MS Project ‘critical tasks’

A critical task in MS Project is a task which has no ‘slack’. This was earlier defined as the number of days that a task can run over schedule. In the context of the Critical Path, it means more specifically "the amount of time that a task can slip before it affects another task or the project’s finish date." The MS Project Critical Path is therefore made up of tasks locked end-to-end in task dependency.

Display your Critical Path with MS Project

The quickest way to view your project’s Critical Path with MS Project is to open the View menu, click on More Views, select Detail Gantt, and then click Apply. This displays all the tasks necessary to complete a project. Critical tasks are displayed as red bars along a horizontal axis measured in project time. The ‘filter’ function can then be used to display critical (or, if required, non-critical) tasks only.

Shorten the Critical Path with MS Project

Sometimes the project manager needs to bring forward the finish-date of the project. This can be achieved using MS Project through the following activities:

• Shorten the duration of individual tasks

o schedule overtime

o break a task down into smaller components that can be worked on simultaneously

o assign additional resources to a task

• Create a more flexible schedule

o revise or remove task dependencies

o change task constraints

More than one Critical Path

Most complex projects will have more than one sequence of essential, interdependent project tasks. The MS Project Critical Path will be the main Critical Path for the project, but you can display multiple chains of tasks within a project and even within a programme. It is also possible, using MS Project, to create a portfolio or programme Critical Path, enabling the project manager to evaluate each task against the overall business strategy.

Understanding the Critical Path Method

The Critical Path Method is an essential technique for any professional project manager. Mainstream project management software such as MS Project enables project managers to easily create and manage a Critical Path, and maximise the accuracy and benefits that Critical Path Analysis brings to a project or programme.