Critical path analysis ("CPA") is a widely-used project management tool that uses network analysis to help project managers to handle complex and time-sensitive operations. Show
IntroductionMany larger businesses get involved in projects that are complex and involve significant investment and risk. As the complexity and risk increases it becomes even more necessary to identify the relationships between the activities involved and to work out the most efficient way of completing the project. The essential technique for using CPA is to construct a model of the project that includes the following:
Using this information, CPA calculates:
This process determines which activities are "critical" (i.e., on the longest path) and which have "total float" (i.e. can be delayed without making the project longer). In project management, a critical path is: The sequence of project activities which add up to the longest overall duration The critical path determines the shortest time possible to complete the project. Any delay of an activity on the critical path directly impacts the planned project completion date (i.e. there is no float on the critical path). Illustration of CPAHere is worked example to illustrate how the critical path for a project is determined. Conventions in drawing the network The main components of a network analysis are summarised below:
Example network diagram Consider the following series of activities in a business planning to launch a new product:
Laid out in the correct sequence of activities, the network diagram would look like this before we calculate the EST and LFT for each activity:
The next step is to calculate the EST for each activity. For example: The EST for task B is 2 months – the time taken to conduct market research (task A) To calculate the EST for task C, we add the 2 months for task A to the 4 months for designing the product concept (task B) = 6 months The remaining ESTs can then be added to the network diagram:
The LFTs show the latest time an activity must be completed by to avoid a delay to the project. LFTs are calculated by looking right to left on the network diagram. So:
Evaluating CPAThe main advantages and disadvantages of a business using CPA can be summarised as follows: Advantages of CPA
Disadvantages of CPA
A PERT chart, sometimes called a PERT diagram, is a project management tool used to schedule, organize and coordinate tasks within a project. It provides a graphical representation of a project's timeline that enables project managers to break down each individual task in the project for analysis. The PERT chart template uses nodes -- drawn as rectangles or circles -- to represent events and milestones throughout the project. The nodes are connected by vectors -- drawn as lines -- which represent the various tasks that need to be completed. PERT charts provide project managers with an estimation of the minimum amount of time needed to complete a project. Managers can also analyze the work breakdown and task connections, as well as assess the risk associated with the project. The breakdown structure makes it easy to organize a complex project with a variety of moving parts by visualizing the dependencies between each step of the process. PERT stands for Program Evaluation Review Technique, a methodology developed by the U.S. Navy in the 1950s to manage the Polaris submarine missile program. A similar methodology, the critical path method (CPM) was developed for project management in the private sector at about the same time.
TerminologyHere is a list of terms associated with PERT charts:
How a PERT chart worksA PERT chart presents a graphic illustration of a project as a network diagram consisting of numbered nodes linked by labeled vectors. The direction of the arrows on the lines indicates the sequence of tasks. When creating a PERT chart, project managers should follow the below steps:
Once the PERT chart is drawn, project managers can use it to develop a realistic time frame for the project:
A breakdown of a PERT chart In the diagram, for example, the tasks between nodes 1, 2, 4, 8 and 10 must be completed in sequence. These are called dependent or serial tasks. The tasks between nodes 1 and 2 and nodes 1 and 3 are not dependent on the completion of one to start the other and can be undertaken simultaneously. These tasks are called parallel or concurrent tasks. Tasks that must be completed in sequence but that don't require resources or completion time are considered to have event dependency. These are represented by dotted lines with arrows and are called dummy activities. For example, the dashed arrow linking nodes 6 and 9 indicates that the system files must be converted before the user test can take place but that the resources and time required to prepare for the user test -- writing the user manual and user training -- are on another path. Numbers on the opposite sides of the vectors indicate the time allotted for the task. When to use a PERT chartPERT charts should be used when a project manager needs to:
Project managers find best results when they use a PERT chart at the beginning of the project. Doing so helps ensure the project is accurately scoped and can help avoid any potential bottlenecks in the process. Advantages of PERT chartsProject managers use PERT charts to gain these benefits:
Disadvantages of PERT chartsDisadvantages of the PERT chart include the following:
PERT chart vs. Gantt chartThe PERT chart is sometimes preferred over the Gantt chart, another popular visual tool for project managers, because it clearly illustrates task dependencies. On the other hand, the PERT chart can be more difficult to interpret, especially on complex projects. Frequently, project managers use both techniques.
This was last updated in February 2021 Continue Reading About PERT chart
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What is the longest sequence of activities in a project?The critical path is the longest sequence of activities in a project plan which must be completed on time for the project to complete on due date.
Which is the best project management tool to use to determine the longest time the project will take?Critical Path Method
This is because this tool can monitor and assess the progress of the project in real-time. It is to ensure that all the ongoing projects performed by the team are going to finish in time. The Critical Path of the project is the longest sequence of activities performed on the network diagram.
What is the longest path of tasks to be completed?A critical path is a sequence of interdependent activities or tasks that must be finished before the project can be finished. It is the longest path (i.e. path with the longest duration) from project start to finish.
Is the sequence of activities in the project that comprise the longest possible time duration throughout the network from start to finish?In a project network, the critical path is the sequence of activities which has D. the longest time. A critical path tells us the longest duration to finish the activities of a project on time. The critical path includes slack time without causing delays.
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