Critical Path Analysis

12 Key excerpts on "Critical Path Analysis"

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  eBook - PDF

  Building a Project Work Breakdown Structure

  Visualizing Objectives, Deliverables, Activities, and Schedules

  • Dennis P. Miller, J. LeRoy Ward(Authors)
  • 2008(Publication Date)
  • Auerbach Publications

    (Publisher)

  115 Chapter 12 Step 8 Verify the Project Timeline Background “Verifying the project timeline” is really nothing but performing network mathemat-ics. Its prime purpose is to determine whether the project team can meet or exceed the targeted endpoint (timeline). In addition, while performing this step; the team acquires an understanding of how the critical path affects them and their individual activities. To the facilitator, an advantage of Critical Path Analysis (CPA) is to keep the planning team fully engaged in the planning process. The mathematics of CPA are simple and can be performed without either a calculator or PC software. It completes the network math-ematics set of PERT (Program Evaluation Review Technique). PC software can perform this step but for the sake of maintaining the planning team’s interest, it is best performed at this time and manually . One of the “hidden” controversies in project management revolves around how CPA should be performed. There are three methods: (1) the all paths method, (2) the one method, and (3) the zero method. Interval mathematics is the basis for CPA, and the essential difference between the zero and one methods is how to manage the “interval.” JIT Training T hree CPA Methods There are three different methods to perform CPA. They were all developed for different purposes. All three methods will arrive at the same endpoint date but will have different intermediate dates. 116 n Building a Project Work Breakdown Structure Dates versus Absolute Days When we speak of “dates,” we are really referring to absolute periods. When per-forming CPA, we are dealing with whole numbers (1, 23, 51, etc,) representing your minimum period of lapse time — most frequently “days.” All Paths Method The all paths method is the simplest method and was developed to determine quickly the critical path. This method requires you to first identify all the different paths through the network.

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  Critical Path Analysis and Linear Programming

  • Mik Wisniewski, Jonathan H Klein(Authors)
  • 2017(Publication Date)
  • Red Globe Press

    (Publisher)

  It tends to focus on the ‘big picture’, and typically the networks upon which it would be framed would consist of relatively few ‘high-level’ activities. Critical Path Analysis would be expected to inform project risk analysis, however. For a thorough treatment of project risk analysis, see, for example, the book by Chapman and Ward (1997). 164 Critical Path Analysis 11.1 Introduction Critical path network analysis techniques are regarded as one of the ‘classic’ mathematical operational research topics, along with such other topics as linear programming, inventory modelling, and computer simulation. For this reason, introductory treatments are to be found, as a rule, in most general OR texts. However, they are not, and should not be regarded as, exclusive to OR, and similar introductory treatments can be found in general texts on operations management and project management, in particular. More specialized texts, dedicated to the topic, are also available, pitched at a range of categories of reader. Finally, the research literature abounds with papers describing both theoretical and practical developments in the area, as well as review articles and case studies. 11.2 Introductory material Most general text books on operational research contain a chapter or so on critical path network analysis techniques, though there are some exceptions. These treatments are generally pitched at about the mathematical level of this book, though the chattiness varies considerably from book to book. The treatments generally focus on manual techniques for, in particular, developing and using both deterministic (CPM) and probabilistic (PERT) AOA diagrams. Anderson et al. (1994), Render and Stair (1994), and Waters (1989), for example, provide accounts that are particularly accessible to non-mathematical readers. By contrast, authors such as Taha (1987) and Winston (1994) tend to assume more mathematical sophistication in their readers.

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  The Sports Management Toolkit

  • Paul Emery(Author)
  • 2011(Publication Date)
  • Routledge

    (Publisher)

  CHAPTER 7

  CRITICAL PATH NETWORKS:COMPLETING PROJECTS ON TIME

  TECHNIQUE DESCRIPTION

  Critical path networks are diagrammatic representations of related tasks that collectively constitute a project. Being derived directly from project management theory, they provide managers with important resource planning information regarding the effective use of time. As well as simplifying complex projects, critical path networks can estimate the length of the total project and help you to identify the ‘critical’ tasks that must be completed on time for the project to meet its scheduled finish date.

  The process of creating critical path networks involves the use of several project management techniques that have evolved and been integrated into various hybrid versions over time. Within this chapter the following project management processes and outputs will be introduced to you:

     work breakdown structure (WBS) – dividing projects into smaller, manageable, independent and measurable sub-components;

     Gantt charts – scheduling project tasks graphically, displayed via horizontal bars that represent time;

     resource allocation – assigning human and financial units to a project or individual tasks;

     activity sequencing – determining task dependencies and the nature of the logical relationships between them;

     Critical Path Analysis (CPA) – depicting activities or tasks as a logical diagram that aids management decision making.

  To better understand project management outputs and decisions, this chapter will first introduce you to manual processes, before progressing to contemporary computer applications, demonstrating their practical use through an applied sports management example.

  PURPOSE

  Critical path networks, particularly through computer applications such as Microsoft Project™ and ProjeX, permit managers to effectively plan and control complex projects. By pictorially displaying key information in different formats, sport managers can:

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  Managing Projects as Investments

  Earned Value to Business Value

  • Stephen A. Devaux(Author)
  • 2014(Publication Date)
  • CRC Press

    (Publisher)

  Perhaps what causes some to ignore critical path planning is the fact that the initial critical path schedule will almost never be achieved in actuality. Technical problems will arise, expected resources will be absent, there will be a gap in “work hand-offs,” and the critical path itself 61 Chapter four: Managing project time will quite likely migrate to a completely different set of activities. But none of this lessens the benefit of Critical Path Analysis; indeed, the more vari-ances from plan that there are, the more valuable Critical Path Analysis is for measuring impacts and making decisions. It is important to recognize that the critical path may very well turn out to be different from those linked activities that one expected to com-prise the longest path; that path was simply the planned critical path. That said, the project will still be exactly as long as its longest path! The lon-gest path that ultimately determines the length of the project is what in the construction industry is known as the as built critical path (ABCP). This path, with its work delays, technical difficulties, scope changes, and resource insufficiencies, is what ultimately determines the length of the project. And whether it is what was planned or not, it is crucial that the project manager recognize the overwhelming importance of this path, and manage it. During the project postmortem (a vital process at the end of every project that is all too often omitted), this path and the changes from plan that may have triggered it should be a vital artifact. After all, whether the project schedule was ultimately delayed or accelerated, the critical path has almost certainly had an impact on the expected monetary value of the project investment.

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  Project Scheduling Handbook

  • Jonathan F. Hutchings(Author)
  • 2003(Publication Date)
  • CRC Press

    (Publisher)

  4 CPM—Critical Path Management

  DOI: 10.1201/9780203912928-4

  Nomenclature

  Professional project scheduling is built on the fundamentals of the critical path method, or critical path management as it is has evolved to be known as in the industry. Critical path method refers to identifying bottlenecks in the production process and then building a production timeline through them, using the total duration of those activities that will take the longest to complete as the basic timescale. Critical path management is the methodology for managing those timeline paths efficiently, by manipulating time management of the interlinkage of activities durations and contingency workarounds. It is a scheduling system that allows the project scheduler to achieve improved time control over a project’s production phases. Additionally, an audit trail and cost tracking can be incorporated into the system to provide a reasonably accurate estimate of timeframes required for those or similar activities in future projects.

  CPM typically works best in straight-line, time-scaled productions in any business where the timelines can be estimated with a fair amount of certainty. The modern network scheduling software programs are essentially a combination of CPM and S-charts. Critical path management is the most accurate computerized system of network scheduling yet developed. It allows production managers, developers, owners, and prime contractors to achieve control in the following critical areas of project scheduling:

  They can figure out where they stand right now in the project. They can determine where to expect production bottlenecks. They can decide what to do next. They can begin changes today to keep the project on track.

  In the construction industry, repeat business does not just come from simply building something well. The companies that get repeat business do so because they manage projects in ways that protect their clients. CPM scheduling tells the owner where he stands, not only financially but also in terms of issues, problems, and resources on the project. Ultimately, that’s the biggest concern to most owners. CPM has proven itself by adding more bottom line to owners’ investments. In larger projects, such as multiresidential, commercial, industrial, and public works, CPM is mandated by contract.

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  Project Management in Practice, International Adaptation

  • Jack R. Meredith, Scott M. Shafer, Samuel J. Mantel, Jr., Margaret M. Sutton(Authors)
  • 2021(Publication Date)
  • Wiley

    (Publisher)

  (1998, Chapters 5 and 6). Finding the critical path is a fairly straightforward problem in linear programming, but it often takes more time than doing the same problem by hand, and certainly much more time (entering the required information) than letting MSP solve the problem. Following the definition of some terms commonly used in PERT/CPM analysis, both AON and AOA networks are illustrated. ES and EF are found for all network activities, and the critical time and critical path are identified by the forward-pass method. LS and LF are cal- culated for all activities by the backward-pass method, and slack is defined as either LS − ES or LF − EF. The managerial implications of the critical path and of project slack are briefly discussed. The same problem used for illustrating networks is entered into MSP and shown as an output of the software. 5.2 PROJECT UNCERTAINTY AND RISK MANAGEMENT In Section 4.5, Chapter 4 on risk analysis mentioned making most likely (or normal), optimistic, and pessimistic cost estimates for project tasks. Such estimates were shown in Table 4.6, and we promised to illustrate how to use these and similar estimates of task duration to determine the likelihood that a project can be completed by some predetermined time or cost. It is now time to keep that promise. 5.2.1 Calculating Probabilistic Activity Times First, it is necessary to define what is meant by the terms “pessimistic,” “optimistic,” and “most likely” (or “normal”). Assume that all possible durations (or all possible costs) for some task can be represented by a statistical distribution as shown in Figure 5.13. The individual or group mak- ing the estimates is asked for a task duration, a, such that the actual duration of the task will be a or lower approximately 3 times out of 1,000 times.

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  Available until 8 Dec |Learn more

  Project Management for the Oil and Gas Industry

  A World System Approach

  • Adedeji B. Badiru, Samuel O. Osisanya(Authors)
  • 2016(Publication Date)
  • CRC Press

    (Publisher)

  113 5 Critical Path Method for Oil and Gas Projects On the critical path, the shortest distance between two poor points is a curve. Like a pipeline network, activities that make up a project form a network of interrelationships. Consider the network in Figure 5.1. The complexity of the activity network in a large project increases rapidly with increase in the number of activities. Network analysis is essential for making sense out of the jumble of activities. Project scheduling is the time-phased sequencing of network activities subject to precedence relationships, time constraints, and resource limitations to accomplish specific objectives. The computational approaches to project network analysis using PERT, CPM, and PDM (prece-dence diagramming method) are presented. Several graphical variations of Gantt charts are presented. CPM network charts and Gantt charts are excel-lent visual communication tools for conveying project scope, requirements, and lines of responsibility. Because of the long-run nature of large projects in the oil and gas industry, activity scheduling and long-term coordination are very important. There are five main categories of scheduling as listed below: 1. Stochastic project scheduling 2. Fuzzy project scheduling 3. Proactive project scheduling 4. Reactive project scheduling 5. Hybrid predictive project scheduling Stochastic scheduling recognizes the fact that variability exists in the attributes of the schedule elements. These could be in terms of time, cost, requirements, and human resources. Fuzzy scheduling considers the impre-cision associated with the parameters of the activities in the project schedule. Instead of precise parameter end points, we have shades of overlap of param-eter values. In proactive scheduling, advance contingencies are built into the project schedule. This can be very useful in preempting problems in the proj-ect schedule down the line.

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  Basic Business Analysis and Operations Research

  • R H Mole(Author)
  • 2013(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  C h a p t e r 5 Critical path network analysis Essential theory 5.1 Introduction The launch of a new product, an increase in manufacturing capacity, or perhaps the commissioning of a computerized accounts system are examples of major projects. In every case a major project management team will find it necessary to plan the project, and then control its execution. These can be formidable tasks if the project is capital intensive, involves a complex set of interrelating factors, and if the success of the project is vital to long-term development. Further difficulties arise when it is necessary to coordinate a range of activities, each with its own demands upon managements' time and resources. Network analysis has been developed specifically to assist the project manager to understand the ramifications for the project as a whole of the detailed arrangements of individual aspects. It is applied as a routine in large civil engineering projects. But there is hardly an area of industry or commerce which has not had recourse to network analysis at some time to assist the rational management of projects of every conceivable description. A small-scale project has been chosen here as a vehicle for describing the methodology. Even so the reader may well come to a favourable judgement on the utility of the approach. We suppose that a company has decided to introduce a modern system of networked micros for automating the routine clerical tasks of an existing accounts office. This project clearly involves a range of preparatory activities. At the very least, these will include: the collection of information about suitable systems; the recruitment of systems analysts; the development of new accounting systems and procedures; training existing staff in the new methods; making arrangements to phase out the old and phase in the new; and organizing maintenance contracts for the new equipment.

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  Project Management

  Systems, Principles, and Applications, Second Edition

  • Adedeji B. Badiru(Author)
  • 2019(Publication Date)
  • CRC Press

    (Publisher)

  TS s. The steps for determining the critical path from the forward pass only are as follows:

  1. Complete the forward pass in the usual manner.
  2. Identify the last node in the network as a critical activity.
  3. If activity i is an immediate predecessor of activity j , which is determined as a critical activity, then check ECi and ESj . If ECi = ESj , then label activity i as a critical activity. When all immediate predecessors of activity j are considered, mark activity j .
  4. Continue the backtracking from each unmarked critical activity until the project starting node is reached. Note that if there is a single starting node or a single ending node in the network, then that node will always be on the critical path.

  Subcritical Paths

  In a large project network, there may be paths that are near critical. Such paths require almost as much attention as the critical path since they have a high potential of becoming critical when changes occur in the network. Analysis of subcritical paths may help in the classification of tasks into A, B, and C categories on the basis of Pareto analysis. Pareto analysis separates the “vital” few activities from the “trivial” many activities. This permits a more efficient allocation of resources. The principle of Pareto analysis originated from the work of Italian economist Vilfredo Pareto (1848–1923). In his studies, Pareto discovered that most of the wealth in his country was held by a few individuals.

  For project control purposes, the Pareto principle states that 80% of the bottlenecks are caused by only 20% of the tasks. This principle is applicable to many management processes. For example, in cost analysis, one can infer that 80% of the total cost is associated with only 20% of cost items. Similarly, 20% of an automobile’s parts cause 80% of maintenance problems. In personnel management, about 20% of employees account for about 80% of absenteeism. For Critical Path Analysis, 20% of the network activities will take up 80% of our control efforts. The ABC classification based on Pareto analysis divides items into three priority categories: A (most important), B (moderately important), and C (least important). Appropriate percentages (e.g., 20%, 25%, 55%) are assigned to the categories.

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  Handbook of Industrial Engineering Equations, Formulas, and Calculations

  • Adedeji B. Badiru, Olufemi A. Omitaomu(Authors)
  • 2010(Publication Date)
  • CRC Press

    (Publisher)

  In this case, the deadline of 18 days occurs after the EC of the last node in the network. Calculations for Subcritical Paths In a large project network, there may be paths that are near critical. Such paths require almost as much attention as the critical path because they have a high risk of becoming critical when changes occur in the network. Analysis of subcritical paths may help in 10 -10 Handbook of Industrial Engineering Equations, Formulas, and Calculations 2 6 14 2 13 0 2 11 13 5 16 A 2 D 3 B 6 G 2 F 4 0 6 10 16 16 11 End 9 16 E 5 11 11 18 18 18 9 18 Critical path Deadline Earliest completion C 4 4 4 11 11 Start 0 7 0 7 0 7 FIGURE 10.5 CPM network with deadline. the classification of tasks into ABC categories on the basis of Pareto analysis, which separates the most important activities from the less important ones. This can be used for more targeted allocation of resources. With subcritical analysis, attention can shift from focusing only on the critical path to managing critical and near-critical tasks. Steps for identifying the subcritical paths are as follow: Step 1: Sort activities in increasing order of total slacks. Step 2: Partition the sorted activities into groups based on the magnitudes of total slacks. Step 3: Sort the activities within each group in increasing order of their ESs. Step 4: Assign the highest level of criticality to the first group of activities (e.g., 100%). This first group represents the usual critical path. Step 5: Calculate the relative criticality indices for the other groups in decreasing order of criticality. The path’s criticality level is obtained from the formula λ = α 2 − β α 2 − α 1 × 100, where α 1 is the minimum total slack in the network, α 2 the maximum total slack in the network, and β the total slack for the path whose criticality is to be calculated. The above procedure yields relative criticality levels between 0% and 100%. Table 10.3 presents an example of path criticality levels.

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  Total Project Control

  A Practitioner's Guide to Managing Projects as Investments, Second Edition

  • Stephen A. Devaux(Author)
  • 2015(Publication Date)
  • CRC Press

    (Publisher)

  85 chapter six Scheduling I: The critical path method (CPM) Project management is about planning your project in a flexible format so that you can adjust to changes when they occur. Nowhere is that “flexible” format more in evidence than in CPM scheduling. History of the critical path method Most project management literature puts the birth of modern project man-agement as 1957 or 1958. These are the years in which CPM and PERT (program evaluation and review technique) were developed in the con-struction and defense industries, respectively. Today the two terms are used more or less interchangeably. When the boss says to give him a PERT chart of this project, chances are that he is asking for a CPM-derived net-work logic diagram of the activity schedule, even though PERT actually means something slightly different. In 1964, IBM project managers developed an “enhancement” of the traditional CPM network logic diagram called the precedence diagram method (PDM). “Enhancement” is used here in quotes because it is argu-able if it really represented a step forward. The argument, however, is somewhat mooted by the fact that the method has become commonplace, and is included under the name CPM in just about all project manage-ment software packages. There are two different diagramming techniques used for display-ing CPM workflow: activity-on-node (AON) and activity-on-arrow (AOA) diagrams. In AON diagramming, the activity is represented by a box or a node, while the predecessor/successor relationship is represented by an arrow pointing from the predecessor to the successor. Figure 6.1 shows an AON diagram with Activity A as a predecessor of both B and C, and both B and C being predecessors of D. AON is by far the more intuitive and simpler method of diagramming CPM. With AOA, the arrow represents both the relationship and the activ-ity, as an arrow running between the start of an activity and its finish.

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  Managing Aviation Projects from Concept to Completion

  • Triant G. Flouris, Dennis Lock(Authors)
  • 2016(Publication Date)
  • Routledge

    (Publisher)

  14Critical Path Network Analysis in More Practical Detail

  The previous chapter explained the concept and basic theory of Critical Path Analysis. Both the arrow and precedence network methods were introduced and illustrated using a case example. This chapter begins by examining some of the more practical, ‘hands on’ aspects of constructing a plan for a new project. We shall then explain some variants or slightly more advanced applications of critical path network analysis, again illustrated with case examples.

  MAKING A DETAILED PLAN FOR A NEW PROJECT

  It should be apparent that an overall project network diagram and schedule can engender a number of sub-plans. This is particularly true for many aviation projects, where major sub-contractors or partners will carry out substantial parts of the project in separate premises, using plant, equipment and staff that are not directly employed or controlled by the main contractor. Every one of these partners and sub-contractors will need to make their own detailed plans to fit within an overall planning framework determined by the main contractor. So we need to be clear that the first project planning meeting, which is the subject of this chapter section, often sets out to produce a master network diagram and project schedule into which all the partners and sub-contractors must subsequently fit their own detailed plans.

  The First Planning Meeting: Who Should be There?

  Every project working plan should enshrine a consensus of the ideas and commitments of those who will have to manage work on the project. This implies that the initial critical path network should be sketched at a meeting where the planner can obtain the best possible advice on what tasks need to be included, how they should be sequenced, what resources they will need and how long the responsible manager or engineer expects that each task will take.

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