Key Steps used in Critical Path Method Project
Planning are
1. All activities are specified
2. The Activity Sequences are established
3. A network diagram is produced
4. Estimate the completion time for each activity
5. Identify the critical path (longest path through the network)
6. Update the CPM diagram as the project progresses
1. Specifying Activities
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Based on the work breakdown structure (WBS), a list of all the activities in the project is produced. This listing is used as the basis for additional sequence and duration information.
Based on the work breakdown structure (WBS), a list of all the activities in the project is produced. This listing is used as the basis for additional sequence and duration information. 2. Establishing Activity Sequence
Determine the correct sequence of the tasks. I do this by asking three questions for each task:
i.Which tasks must happen before this one can begin?
Which tasks must happen before this one can begin? ii.Which tasks can be done at the same time as this one?
Which tasks can be done at the same time as this one? iii.Which tasks should happen immediately after this one?
Which tasks should happen immediately after this one? A table is produced using this data - four columns:-prior tasks, this task, simultaneous tasks, following tasks.
3. Producing Network Diagram
After the activities and their sequencing are defined, the CPM diagram will be drawn. Primavera will be used to produce the Network Diagram.
4. Determining Activity Durations
Activity durations are determined based on metrics, past experience or the estimates of knowledgeable persons. Records are kept as to how the estimated durations were derived and from what source of information. the Critical Path Method is a deterministic model that does not take into account variation in the completion time, so only one number can be used for an activity's time estimate.
5. Identifying the Critical Path
The following four parameters for each activity are determined:
i.ES - earliest start time - The earliest time at which the activity can start given that its precedent activities must be completed first.
ES - earliest start time - The earliest time at which the activity can start given that its precedent activities must be completed first. ii.EF - earliest finish time - Equal to the earliest start time for the activity plus the time required to complete the activity.
EF - earliest finish time - Equal to the earliest start time for the activity plus the time required to complete the activity. iii.LF - latest finish time - The latest time at which the activity can be completed without delaying the project.
LF - latest finish time - The latest time at which the activity can be completed without delaying the project. iv.LS - latest start time - Equal to the latest finish time minus the time required to complete the activity.
LS - latest start time - Equal to the latest finish time minus the time required to complete the activity. The Float (slack time) for all activity are determined (the time between its earliest and latest start time, or between its earliest and latest finish time). Float is the amount of time that an activity can be delayed past its earliest start or earliest finish without delaying the project. The critical path is the longest-duration path through the network. The activities that lie on the critical path are those that cannot be delayed without delaying the project. The critical path is the path through the project network in which none of the activities have float, that is, the path for which ES=LS and EF=LF for all activities in the path.
6. Updating the CPM diagram
The CPM is updated as the project progresses. The task completion times will be known and the network diagram will be updated to include this information. A new critical path will emerge, and structural changes can be made in the network if project requirements change.
The Critical Path Method (CPM)
What is the Critical Path?
The Critical Path Method (CPM) enables the project Critical Path to be determined. This is a sequence of activities through a project network from start to finish. There may be more than one Critical Path depending on workflow logic. A delay to progress of any activity on the Critical Path will (without acceleration or re-sequencing) cause the overall project duration to be extended. This is known as a ‘critical delay'.
What is the Critical Path Method (CPM)?
The Critical Path Method is a mathematically based algorithm for scheduling project activities. It was developed in the 1950s in a joint venture between DuPont Corporation and Remington Rand Corporation, specifically for managing plant maintenance projects. Whilst the method was developed for construction, this method of scheduling can be applied to any project with interdependent activities.
The Critical Path Method, which is also sometimes referred to as Critical Path Analysis (CPA) method, deduces the critical activities in a programme by tracing the logical sequence of tasks that directly affect the completion date of the project
It is a methodology or management technique that determines a project's critical path. CPM provides the following advantages:
1. Determines the time to complete the project and key milestones
2. Allows tracking of critical activities
3. Provides a visual presentation of the project
4. Can incorporate the concepts of random predictions, using (PERT)
CPM models the activities and events of a project as a network. There are two main types of logic diagrams:
1. Arrow Diagram (AOA)
2. Precedence Diagram (AON) Arrow diagrams consist of arrows and nodes plus letters and numbers for labelling and calculation purposes
