Schedule DevelopmentNumerous projects was unsuccessfulto meet schedule predictionbecause of lack of schedule development To overcomethis there are methods which are used for project schedule. such as critical path method and pert method 1. Critical path method (CPM)Critical path method or critical path analysismethod.
It is a network connection diagram approachused to approximate total projecttime duration. The network diagram will have the nodes having connection .used forwardpass and backward pass approach to find the rout .
This tool will help you reduce project schedule overruns. A criticalpath for a project is the series of activities that determine the earliest timeby which the project can be finish. Thereare many tasks done in equivalent onprojects, and most of projects have severalpaths through a network diagram chart. The longest path is nothing but criticaltasks is what is driving the completion date for the project. You are notfinished with the project until you have finished all the tasks.For calculating the Critical Path for aproject, we mustCreate a network diagram which requires aactivity list which is project based .
Once after creating a network diagram, wemust also approximate the duration of each activity to determine the criticalpath. Calculation of critical path involves adding the time durations taken byall activities on each path through the network diagram. The longest path isthe critical path. For example:The critical path is the chain of activities withthe longest time taken duration.
A slow up inany of these activities will result in a delay for the whole project. this critical path example help usto understand the how this method work. Using the Critical Path Method (CPM)Theduration of each activity is listed above each node in the diagram. For eachpath, add the duration of each node to determine it’s total duration. Thecritical path is the one with the longest duration. Thereare three paths through this project.Start-> Activity1->Activity3->Activity4->finish 3+7+2=12Start-> Activity2->Activity3->Activity4->finish 5+7+2=14 (Critical Path)Start-> Activity2->Activity5-> finish 5+4=9 Advantages of CPM· Makes dependencies visible between the projectactivities· Increases visibility of impact of schedule revisions· Enables the Project Manager to optimize efficiencyDisadvantages of CPM· For large and complex projects, there’ll be thousands ofactivities and dependency relationship· The Critical Path Method does not accountfor resource and resource allocation 2.
Program Evaluation and Review Technique (PERT) PERT was initially used by defiance in their Polarisproject .In this method, the activities time duration is found using these followingformula:Duration = And,Standard Devation = A network analysis method is used to approximateproject time duration when there is a unpredictabilityabout the individual activity time duration approximates. PERT applies thecritical path method (CPM) to a weighted average time duration approximate.This approach was developed about the same time as CPM, in the late 1950s, andalso uses network diagrams concept, which are still sometimes referred to asPERT charts. PERT uses probabilistic time approximates duration.
Approximationbased on using optimistic time, most likely time , and pessimistic time approximates of activity durations instead ofone specific or discrete duration approximate, as CPM does .By using the PERTweighted average for each activity duration approximate, the total projectduration approximate takes into account the risk or uncertainty in theindividual activity estimate. For example:Suppose A project team in the project caseused PERT to determine the schedule for the online application registrationsystem project. They would have to collect data for the optimistic, mostlikely, and pessimistic duration approximates for each project activity. Supposeone of the activities was to design an input screen for the system. Someonemight approximate that it would take about two weeks or 10 workdays to do thisactivity.
Without using PERT, the duration approximate for that activity wouldbe 10 workdays. Using PERT, the project team would also need to approximate thepessimistic and optimistic times for completing this activity. Suppose anoptimistic approximate is that the input screen can be designed in eight workdays,and a pessimistic time approximate is 24 workdays. Applying the PERT formula:PERT weighted average = = 12Instead of using the most likely duration approximateof 10 workdays, the project team would use 12 workdays .These additional twodays could really help the project team in getting the work completed on time. Advantage of PERT· A PERT chart makes planninglarge projects easier· PERT is a way of makingrelationships visible in a diagram· PERT makes the critical pathvisibleDisadvantage of PERT· PERT charts can becomplicated and confusing, with hundreds or even thousands of tasks anddependency relationships· PERT diagrams can be expensiveto develop, update and maintain.· PERT charts depend on theability to predict precise time frames for multitudes of tasks