The critical path method (CPM) is a progressive project management technique to separate critical and non-critical tasks in order to avoid bottlenecks and missed deadlines due to lack of priorisation. It's best suited for projects with a diverse range of activities in a way that enables their solving in an ordered manner. ideally, a flowchart is used for displaying how the tasks relate to each other (e.g.: how the output of an activity is the input of a subsequent process). It's also tops to determine beforehand the expected completion time for each task.
An activities model designed for project management, common elements of this model include time for the completion of each activity, the dependencies therein, milestones and deliverables. It makes use of the presentation capabilities of an operation flowchart, the outcomes pictured as knots while the accompanying relationships are represented by arrows. For this model to make sense, all individual project operations should be plotted with their respective durations.
Using the dynamics of the operation-duration relationships, CPM calculates the longest path of planned activities to logical end points or to the end of the project, and the earliest and latest that each activity can start and finish without delaying the whole project, as a means of providing a safe margin for work within a given deadline. This procedure distinguishes activities between "critical" and which have "total float", meaning, allowed some delay without compromising the project overall. This network of activities and their matching duration defines the shortest possible time to carry a project through to completion, with total float being unused time within the critical path.
