Difference Between PERT and CPM

Difference Between PERT and CPM

Any project requires the accomplishment of numerous interrelated tasks using limited resources such as money, labor, materials, and time. The success of an organization is highly dependent on excellent project management skills, which are essential for estimating the financial and time requirements to achieve project objectives. The two common statistical methods for ensuring project cost and time effectiveness are PERT and CPM. The Program (Project) Management and Review Technique (PERT) is ideal for projects where it is not known how long it will take to complete certain tasks. The Critical Path Method (CPM), on the other hand, is suitable for projects that are predictable.


The critical path method ( CPM). This is a project modeling method used to efficiently plan project activities. This model is used to determine how long an activity typically takes. According to CPM, each activity can potentially begin at any time between the earliest and latest allowable times. The critical path is determined because, as the name implies, if one activity is delayed, all other activities must also suffer.

All activities that must be performed or completed for the project to be finished are listed in CPM. After that, the order is maintained because several activities depend on earlier ones. In simple terms, this means that some activities will not begin until the previous activity is completed. then makes an estimate of how long it will take to complete each activity. A critical path is then chosen. The critical path is the longest set of tasks that must be completed by a certain date.

CPM – Features

  • Dupont created CPM, to address issues related to project planning. It is necessary to perform a critical path analysis to estimate the date of completion of the project.
  • The critical path method, also known as critical path scheduling, is the most widely used scheduling technique. It is used to calculate the minimum completion time for a project, as well as the possible start and finish times for project activities.
  • The critical path method has quickly differentiated itself from projects in agriculture and construction, which were primarily concerned with avoiding mundane tasks.
  • CPM can be used to determine both the latest and the earliest possible start time for each activity.
  • Distinguishing between non-critical and critical activities is a goal of the CPM procedures. This is done to save time and avoid the formation of long queues.
  • Using CPM, a list of tasks required to complete the project is created. Then the time needed for each task is calculated. After that, the dependencies between all activities must be determined.

CPM – Advantages

  • Helps to compare the plan with the actual state.
  • Identifies all urgent tasks to focus on.
  • Makes dependencies transparent and clear.
  • The technique provides a clear graphical representation of the project.
  • It describes what is most crucial.
  • It also takes into account the sources needed for the project.
  • It is very helpful in calculating the cost and completion date of the project.
  • Reduces the time needed and helps in scheduling.


Program (Project) Evaluation and Review Technique, also known as PERT, is a method for organizing, coordinating, and controlling uncertain activities. The technique analyzes and visualizes the tasks performed to complete a project to determine the shortest time required to complete each task and the shortest time required to complete the entire project. PERT These charts are similar to Gantt bar charts but are often more difficult to interpret because they show the interdependencies between tasks. Pert was developed in the late 1950s during the production of the UGM-27 rocket. It was then used in the Winter Olympics from 1965 to 1968. The main goal of this technique is to reduce the cost and duration of the project.
Analyzing the different tasks in a project and estimating the time needed for each task is helpful for project managers. Using the project evaluation and review technique, the project manager can quickly estimate or calculate the minimum time required for the entire project activity.

PERT – Features

  • The U.S. Navy created Pert to support the planning and management of the Polarities missile program. Pert was created primarily to facilitate the scheduling and planning of large, complicated projects.
  • The Program Evaluation Review Technique is referred to as Pert. PERT charts are planning tools that facilitate the planning and coordination of team members in the execution of work.
  • PERT and the critical path are both tools for visualizing the schedule and work that needs to be done for a project.
  • At PERT, three different time estimates can be made when creating a project. These time estimates are about estimating the shortest time each task could take, the maximum likely time, and the longest time the tasks could take if things don’t go according to plan.
  • Since contractor schedules cannot be changed in the usual way, the calculations are done backward from a fixed end date at PERT.

PERT – Advantages

  • The different types of uncertainties can be identified after the critical path analysis at PERT.
  • Pert encourages collaboration between different project departments, which is very beneficial for decision-making.
  • All activities are displayed in the networks, making it easy to determine whether a project can be completed within the desired budget.
  • Visibility of the decisive path.
  • Analysis of activities from the Pert network includes both independent and combined analyses.

Comparison Chart for Difference Between PERT and CPM

Point of ComparisonCPMPERT
Stands ForCritical Path MethodProject Evaluation Review Technique
MeaningCPM is a project management technique that uses only specific (i.e., time-known) project activities,PERT is a project management technique used to manage activities in a project that are unpredictable (i.e., the timing is unknown).
OrientationActivity-oriented technique.Event-oriented technique.
Development historyIt was developed in 1957.  It was developed in 1958
Mode Typedeterministicprobabilistic
Focus onA trade-off between money and time. It helps project planners decide which project component to expand or reduce.Based on three estimates in PERT – the most likely, the least promising, and the most promising – schedules are set for estimating project completion.
MethodControl time and costControl time
Appropriate forReasonable time estimateHigh precision time estimate
Suitable for
Non-research projects like building construction, Car production, etc.

Research and Project Development
Activity modelUses for repetitive activities.Uses for non-repetitive activities.
AppropriatenessAppropriate for projects with known outcomes and recurring activities. The time frame of such projects is estimated using realistic forms.Suitable for very accurate time estimation of unexpected projects with unique operations.
Duration of activity In CPM, the total duration of the action can be estimated with reasonable accuracyIn PERT the duration of the activities is not very precise and clear
Critical and Non-critical activitiesDifferentiatedNo differentiation
Dummy activitiesIt uses dummy activities for representing the sequence of activities.It doesn’t use any dummy activities.
Crashing conceptApplicableNot Applicable
Comparison Chart: PERT Vs CPM

CPM is better or PERT?

Depending on the type of activities you want to manage, you need to decide which strategy to use for your project. Choosing between PERT and CPM can be challenging, but ultimately it comes down to whether your organization is working with the known or the unknown, and whether you’re focusing only on time or also on cost. Both strategies help organizations manage risk, reduce delays, and complete projects efficiently.


The techniques of these two powerful and practical project management tools have become more complicated over time. For this reason, CPM and PERT are mostly used in conjunction with projects to ensure that all tasks are completed properly. In this article, we have presented the main differences between PERT and CPM. If you have any further questions, feel free to contact us. We will help you as soon as possible.

We also invite you not to miss our other popular articles such as Race vs Ethnicity, How to screenshot on Mac, How to get rid of bed bugs, Medicare vs Medicaid, Difference Between MacBook Air and Pro, and Alligator vs Crocodile.

Resources of Difference between PERT and CPM





Leave a Reply

Your email address will not be published. Required fields are marked *