PERT-CPM Method PDF

PRODUCTION CONTROL GANTT CHARTS An early pioneer in scientific management was Henry L. Gantt, who is best known for his contributions to production planning and controlling. Gantt was the first to devise a reliable method for reserving machine time for jobs in production in order to promote the or...

PRODUCTION CONTROL GANTT CHARTS An early pioneer in scientific management was Henry L. Gantt, who is best known for his contributions to production planning and controlling. Gantt was the first to devise a reliable method for reserving machine time for jobs in production in order to promote the orderly flow of work from one machine to the next with a minimum loss of time or delays. NETWORK TECHNIQUES Network techniques were designed to work with projects in which the activities or events are interrelated. This technique for scheduling and controlling uses events (circles) and activities (lines) which have time estimates assigned to them. Events are connected by activities and represent the beginning or starting point for some production operation. Activities lines or arrows show the time required to complete the event from which they emerge. Program Evaluation Review Technique (PERT) is a specific kind of network or critical path programming approach. It works best for new projects with which the production planners have little or no prior experience. PERT assigns four time estimates to activities: the optimistic, the most likely, the pessimistic, and expected time. The expected time (the time the activity is actually expected to take) is based on a probability analysis of the other three time estimates. Critical path methods other than PERT do not make such estimates or assign probabilities to them. The critical path method (CPM) and program evaluation and review technique (PERT) are both project scheduling techniques. Program Evaluation Review Technique (PERT) is a project management planning tool used to calculate the amount of time it will take to realistically finish a project. A critical path in project management is the longest sequence of activities that must be finished on time in order for the entire project to be complete. Any delays in critical tasks will delay the whole project. The critical path uses an algorithm, also referred to as the CPM formula. That algorithm has two parts, the forward pass and the backward pass. The forward pass is determined by using the earliest start for each activity (ES) and the earliest finish (EF). The ES of an activity equals the EF of the one before it. CRITICAL PATH METHOD TEMPLATE Critical Path Method (CPM) Formula Activity: Any specific task that needs time, labor, materials, or other resources to execute. In a network diagram, the arrow represents activity. Dummy activity: A hypothetical activity used to demonstrate a relationship. That activity is represented by a dummy arrow (dashed arrow). Node (event): An event is the beginning or end of an activity that consumes no time, people, materials, or other resources in a specific period. Events: Final result of the completed tasks. Path: Track the connected activities. Network: The combination that defines the project, the activities, and the events. Critical: Any activity, event, or path that delays the completion of the project. Critical path: The longest path in the network diagram. The duration of your project will be impacted by any critical activity delays. The length of the project is determined by the longest path on the network. There can be more than one critical path, and it is mandatory. Critical Activity: Any activity in the schedule that does not possess any float; Total Float=0 Duration: The amount of time required to complete a schedule activity Earliest start time (ES): This is simply the earliest time that a task can be started in your project. Latest start time (LS): This is the very last minute in which you can start a task before it threatens to delay your project timeline. Earliest finish time (EF): The earliest an activity can be completed, based on its duration and its earliest start time Latest finish time (LF): The latest an activity can be completed, based on its duration and its latest start time Float: Also known as slack, float is a term that describes how long you can delay a task before it impacts its task sequence and the project schedule. The tasks on the critical path have zero float because they can’t be delayed Total Float: is the maximum amount of time an Activity can be delayed without delaying the Project. Free Float: is the amount of time an activity can be delayed without impacting the Early Start date of any of its immediate successors. The critical path method formula has two parts; a forward pass and a backward pass. Forward Pass in CPM Use the CPM diagram and the estimated duration of each activity to determine their earliest start (ES) and earliest finish (EF). The ES of an activity is equal to the EF of its predecessor, and its EF is determined by the CPM formula EF = ES + t (t is the activity duration). The EF of the last activity identifies the expected time required to complete the entire project. Backward Pass in CPM Begins by assigning the last activity’s earliest finish as its latest finish. Then the CPM formula to find the LS is LS = LF – t (t is the activity duration). For the previous activities, the LF is the smallest of the start times for the activity that immediately follows. The Project Network Use of nodes and arrows Arrows: An arrow leads from tail to head directionally – Indicate ACTIVITY, a time consuming effort that is required to perform a part of the work. Nodes: A node is represented by a circle - Indicate EVENT, a point in time where one or more activities start and/or finish. ARROW NETWORK NODE NETWORK