Technology & Engineering
Programme Evaluation and Review Technique (PERT)
PERT is a project management tool used to schedule, organize, and coordinate tasks within a project. It involves creating a network diagram that maps out the sequence and dependencies of project activities, allowing for the estimation of project duration and identification of critical path activities. PERT is particularly useful for complex and non-routine projects where uncertainty and risk are present.
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10 Key excerpts on "Programme Evaluation and Review Technique (PERT)"
eBook - PDFProject Management
A Systems Approach to Planning, Scheduling, and Controlling
- Harold Kerzner(Author)
- 2022(Publication Date)
- Wiley(Publisher)
● PERT is used on those projects, such as R&D, where percent complete is almost impossible to determine except at completed milestones. CPM is used for those projects, such as construction, where percent complete can be determined with reasonable accuracy and customer billing can be accomplished based on per-cent complete. 12.2 GRAPHICAL EVALUATION AND REVIEW TECHNIQUE (GERT) Graphical evaluation and review techniques are similar to PERT but have the distinct advantages of allowing for looping, branching, and multiple project end results. With PERT one cannot easily show that, if a test fails, we may have to repeat the test several times. With PERT, we cannot show that, based on the results of a test, we can select one of several dif-ferent branches to continue the project. These problems are easily overcome using GERT. PMBOK ® Guide, 6th Edition 6.3 Sequencing Activities PMBOK ® Guide, 6th Edition 6.5.2.1 Schedule Network Analysis Dependencies 443 12.3 DEPENDENCIES Developing a network requires an understanding of the dependen-cies between project activities. The project activities that make up the network diagrams usually come from the WBS. However, the type of dependencies that are required may not become evident until the construction of the network and may lead to changes in the WBS. The dependencies can occur at any level of the WBS and may occur at levels higher than work packages even though the schedule may be developed and managed at the work package level.
eBook - ePubThe Dynamic Progress Method
Using Advanced Simulation to Improve Project Planning and Management
- J. Chris White, Robert M. Sholtes(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
The six steps represent the major activities that are conducted in a CPM analysis for a project. As can be seen, this process can be conducted manually, if needed, with pencil and paper. However, there are plenty of currently available software programs that do all this work automatically. One software tool that will be mentioned quite often in this book is Microsoft Project, but there are many more. Due to the ubiquity of Microsoft Office products for many organizations, Microsoft Project is one of the most common off-the-shelf project planning tools, and it provides a good point of comparison as the DPM is discussed.Some Comments on Program Evaluation and Review Technique
It should be noted that the program evaluation and review technique (PERT), developed around the same time as the CPM by Booz Allen Hamilton, the Lockheed Missile System Division, and the US Navy for the Polaris submarine missile program, is another popular project planning and management approach that is often used in conjunction with the CPM. It is not uncommon to see the term PERT/CPM being used to refer to the combined approach. Similar to the CPM, the PERT also incorporates the concept of a critical path, and many of the calculations are the exact same.The major difference with the PERT is that task durations are assigned three values: (1) most likely time (M), (2) optimistic time (O), and (3) pessimistic time (P). Or, sometimes, these are referred to as most likely , best-case , and worst-case times. These different times or durations are used to account for uncertainty: we do not know with exact precision how long a task will take (since we have not done it yet). The PERT then calculates the expected time (duration) for a task to be the following:Expected time = ( O + 4 M + P ) / 6.For example, suppose that the most likely duration for a task is 8 days (M = 8), the optimistic duration is 6 days (O = 6), and the pessimistic duration is 16 days (P = 16). Then, the expected duration would be the following:
eBook - ePubProduction and Operations Analysis
Traditional, Latest, and Smart Views
- Susmita Bandyopadhyay(Author)
- 2019(Publication Date)
- CRC Press(Publisher)
The next step of project execution is project controlling. Management of any organization is always in search of better techniques for controlling the project taken. Controlling of project actually indicates matching what has been planned with the actual progress. Some of the popular controlling techniques are enlisted below. Among these techniques, PERT and Critical Path Method (CPM) are very famous techniques and are described in any book of Operations Research, for example the book by Hillier and Lieberman (2001).• Gantt or bar chart• Milestone chart• Line of balance• Program Evaluation and Review Technique• Critical Path Method (also known as Arrow Diagram Method—ADM)• Precedence Diagram Method (PDM)• Graphical Evaluation and Review Technique (GERT)The above controlling techniques are also the scheduling techniques. Among the above techniques, the methods—PERT, CPM, GERT, and PDM will be described in this chapter. The project can be drawn as a network and can be scheduled effectively. The basic advantages of network scheduling are:• Project scheduling provides guidelines about how to use the resources in order to achieve the target.• Helps to evaluate the alternatives• Provides the basic structure for reporting• Helps to prepare the causes for various incidents• Helps in the risk analysis for the entire projectThis chapter shows various aspects of scheduling starting from Section 17.2 . The next two sections discuss the most popular methods—PERT and CPM.17.2 Program Evaluation and Review Technique (PERT) and Critical Path Method (CPM)
Both PERT and CPM are shown through representing a project through network diagram. Thus, a network is a graphical representation of the activities or operations or tasks of a project. A network diagram shows the dependency of various activities of a project and their inter-relationships. A network diagram is represented graphically by arrows which represent the activities, events, and the numbers of the activities representing the weights of the activities, which may represent durations of the activities or operations, as shown in Figure 17.1
eBook - PDFFundamentals of Infrastructure Engineering
Civil Engineering Systems, Second Edition,
- Patrick H. McDonald(Author)
- 2001(Publication Date)
- CRC Press(Publisher)
c H A p T E R 7 CPM AND PERT 7.1 INTRODUCTION CPM and PERT are acronyms for Critical Path Method and Program Evaluation and Review Technique. These are devices which have been created to facilitate the management of large projects. Essentially, they arise out of the logistics problems associated with complex systems and the need to know the status of and allow control of such mammoth works. Their origins can be traced to times of national emergency in World War I and World War II when it was necessary to create, train, supply, transport, deliver to far-flung theaters of operation, re-supply, maintain, and command large field armies, great task-force fleets, and monster air armadas. Both are network models. Following World War II, the successful aspects of prior methodologies were incorporated into refined schemes applicable to industrial enterprises as well as weapons systems. The exegencies ofthe Cold War, especially the missile gap (real or imagined), the space race, new global military crises in Korea, Cuba, Vietnam, the Middle East, and elsewhere, gave further impetus to their introduction into the fabric of contemporary society. Precisely because huge projects require enormous resources drawn from a limit-ed supply of the same, and just because real-time operations within such projects are governed by the clock, there needs to be a management scheme which will insure that the outcome is satisfactory according to criteria established in ad-vance. Failing this, the ongoing management methods must provide for and allow mid-course corrections to assure an optimum performance. PERT and CPM purport to fulfill these roles. Both are drawn from the reper-tory of that larger, more encompassing realm called Operations Research, a term used to refer to the discipline which specializes in the study of logistic systems. 7.2 CPM The Critical Path Method emerged out of a program begun at E. I. DuPont de Nemours Company in 1956. Mr. M. R. Walker, a DuPont engineer, and Mr.
eBook - PDFProject Management
A Managerial Approach
- Jack R. Meredith, Scott M. Shafer, Samuel J. Mantel, Jr.(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
297 CHAPTER 8 In this and the following three chapters, we continue with the implementation of the project plans we made in Chapter 6. In this chapter, we examine some scheduling techniques that have been found to be useful in project management. We cover the program evaluation and review technique (PERT), Gantt charts, and briefly discuss Precedence Diagramming and report-based methods. Risk analysis and management will be considered as an inherent fea- ture of all scheduling methods, and a simulation of a project schedule will be demonstrated. While the topic of scheduling and particularly the mechanics of project scheduling tend to be more tactical in nature, it is important for the reader to keep in mind that there are important strategic implications associated with project scheduling. For example, in many projects such as the release of a new version of a software product, the construction of an office building, or the upgrade of the latest smartphone, nothing is more visible to senior management and customers than a project that misses its published deadline. In addition to increasing the cost of the project, missed deadlines can seriously damage an organiza- tion’s brand and reputation. And with greatly shorter product lifecycles, missed deadlines can have serious consequences in terms of the ability of the organization to gain market share and may significantly limit the amount of time the organization has to recoup its investment in the project. Therefore, while our discussion of the mechanics of scheduling in this chapter takes a more tactical approach, it is important to not to lose sight of the stra- tegic implications associated with project scheduling. As of tomorrow, employees will only be able to access the building using individual security cards. Pictures will be taken next Wednesday, and employees will receive their cards in 2 weeks.
- Jack R. Meredith, Scott M. Shafer, Samuel J. Mantel, Jr., Margaret M. Sutton(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
We also note some of the strengths and weaknesses of the different displays. In addition, we apply risk management directly to the project schedule. From this analysis, we show how to estimate the likelihood that a project can be completed on or before a specific time. (In Chapter 6, we explore what to do if it appears that the project will not be completed on schedule.) In addition to standard analytic methods for risk management, we once again demonstrate simulation methods. We start with simple plans and schedule them manually. After scheduling by hand, we turn to the computer and use MSP to do our scheduling and many other tasks for us. The same approach is used for risk management. First, problems involving risk will be solved by hand. Once the theory is understood, we use the computer to handle the same problems without so much arithmetic. PMBOK Guide Risk 5.1 PERT AND CPM NETWORKS In the late 1950s, the Program Evaluation and Review Technique (PERT) and the Critical Path Method (CPM) were independently developed. PERT was developed by the U.S. Navy, Booz- Allen Hamilton (a business consulting firm), and Lockheed Aircraft (now Lockheed Martin Corp.); and CPM was developed by DuPont De Nemours Inc. When they were developed, there were significant differences in the methods. For example, PERT used probabilistic (or uncer- tain) estimates of activity durations and CPM used deterministic (or certain) estimates but 152 CHAPTER 5 Scheduling the Project included both time and cost estimates to allow time/cost trade-offs to be used. Both methods employed networks to schedule and display task sequences. (Throughout this chapter, we will use the words “activity” and “task” as synonyms to avoid constant repetition of one or the other.) Both methods identified a critical path of tasks that could not be delayed without delay- ing the project.
eBook - PDF- Daniel W. Halpin, Bolivar A. Senior, Gunnar Lucko(Authors)
- 2017(Publication Date)
- Wiley(Publisher)
9 134 chapter Scheduling: Program Evaluation and Review Technique Networks and Linear Operations 9.1 Introduction Bar charts and critical path method (CPM) networks assume that all activity durations are con- stant or deterministic. 1 An estimate is made of the duration of each activity prior to commence- ment of a project, and the activity duration is assumed to remain the same (e.g., a nonvariable value) throughout the life of the project. In fact, this assumption is not realistic. As soon as work begins, due to actual working conditions, the assumed durations for each activity begin to vary. If a CPM schedule were just to use average durations for each activity (where historical data indicate that 50% of instances were shorter and 50% longer), the probability of finishing the project on time would only be 50%! Clearly, it is important to ask how variable durations will impact the probability of finishing the project in a certain number of days. The variability of project activities is addressed in a method developed by the U.S. Navy at approximately the same time as CPM. This method was called the Program Evaluation and Review Technique (PERT). PERT incorporates means to consider uncertainty in the project planning by assuming that the duration of some or all of the project activities can be variable. The variability is defined in terms of three estimates of the duration of each activity as follows: 1. Most pessimistic duration 2. Most optimistic duration 3. Most likely duration 1. Logic is also considered to be constant or invariable throughout the life of the project for each activity. 9.1 Introduction 134 9.2 An Example Program Evaluation and Review Technique Network 136 9.3 Program Evaluation and Review Technique Shortcomings 139 9.4 Linear Construction Operations 140 9.5 Production Curves 141 9.6 Line of Balance 144 9.7 Line of Balance Applied to Construction 145 Review Questions and Exercises 148
Available until 8 Dec |Learn moreProject Management for the Oil and Gas Industry
A World System Approach
- Adedeji B. Badiru, Samuel O. Osisanya(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
The second approach is a combination of the approach used for the illustrative example and the criticality index approach. It reflects the process of selecting the least-cost expected value. The denominator of the expression represents the expected number of days by which the critical path can be shortened. For different project networks, different crashing approaches should be considered, and the one that best fits the nature of the network should be selected. Program Evaluation and Review Technique The PERT is an extension of CPM that incorporates variability in activity durations into project network analysis. PERT has been used extensively and successfully in practice. In real life, activities are often prone to uncertainties that determine the actual durations of the activities. In CPM, activity dura-tions are assumed to be deterministic. In PERT, the potential uncertainties in activity durations are accounted for by using three time estimates for each activity. The three time estimates represent the spread of the estimated activ-ity duration. The greater the uncertainty of an activity, the wider the range of the estimates. 3400 S 12 S 11 S 9 S 7 S 5 S 10 S 8 S 6 S 4 S 3 S 2 S 1 3200 3000 2800 2600 6 7 8 9 10 11 Duration (T) Cost ($) FIGURE 5.12 Time–cost plots for the strategies in Table 5.5. 133 Critical Path Method for Oil and Gas Projects PERT Formulas PERT uses the three time estimates and simple equations to compute the expected duration and variance for each activity. The PERT formulas are based on a simplification of the expressions for the mean and variance of a beta distribution. The approximation formula for the mean is a simple weighted average of the three time estimates, with the end points assumed to be equally likely and the mode four times as likely.
- A. Ravi Ravindran(Author)
- 2016(Publication Date)
- CRC Press(Publisher)
In deterministic networks, this refers to the critical activities. In stochastic networks, an activity is expected to fall on the critical path only a percentage of the time. The second approach is a combination of the approach used for the illustrative example and the criticality index approach. It reflects the process of selecting the least-cost expected value. The denominator of the expression 15 -18 Operations Research and Management Science Handbook represents the expected number of days by which the critical path can be shortened. For different project networks, different crashing approaches should be considered, and the one that best fits the nature of the network should be selected. 15.3 PERT Network Analysis Program evaluation review technique (PERT) is an extension of CPM that incorporates variability in activity durations into project network analysis. PERT has been used exten-sively and successfully in practice. In real life, activities are often prone to uncertainties that determine the actual durations of the activities. In CPM, activity durations are assumed to be deterministic. In PERT, the potential uncertainties in activity durations are accounted for by using three time estimates for each activity. The three time estimates represent the spread of the estimated activity duration. The greater the uncertainty of an activity the wider the range of the estimates. 15.3.1 PERT Estimates and Formulas PERT uses three time estimates (optimistic, most likely, and pessimistic) to compute the expected duration and variance for each activity. The PERT formulas are based on a sim-plification of the expressions for the mean and variance of a beta distribution. The approx-imation formula for the mean is a simple weighted average of the three time estimates, with the end points assumed to be equally likely and the mode four times as likely.
eBook - PDF- A. Ravi Ravindran(Author)
- 2008(Publication Date)
- CRC Press(Publisher)
In deterministic networks, this refers to the critical activities. In stochastic networks, an activity is expected to fall on the critical path only a percentage of the time. The second approach is a combination of the approach used for the illustrative example and the criticality index approach. It reflects the process of selecting the least-cost expected value. The denominator of the expression 1 -18 Operations Research Applications represents the expected number of days by which the critical path can be shortened. For different project networks, different crashing approaches should be considered, and the one that best fits the nature of the network should be selected. 1.3 PERT Network Analysis Program evaluation review technique (PERT) is an extension of CPM that incorporates variability in activity durations into project network analysis. PERT has been used exten-sively and successfully in practice. In real life, activities are often prone to uncertainties that determine the actual durations of the activities. In CPM, activity durations are assumed to be deterministic. In PERT, the potential uncertainties in activity durations are accounted for by using three time estimates for each activity. The three time estimates represent the spread of the estimated activity duration. The greater the uncertainty of an activity the wider the range of the estimates. 1.3.1 PERT Estimates and Formulas PERT uses three time estimates (optimistic, most likely, and pessimistic) to compute the expected duration and variance for each activity. The PERT formulas are based on a sim-plification of the expressions for the mean and variance of a beta distribution. The approx-imation formula for the mean is a simple weighted average of the three time estimates, with the end points assumed to be equally likely and the mode four times as likely.
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