2 What is a Project?A project is a (temporary) sequence of unique, complex, and connected activities that have one goal or purpose and that must be completed by a specific time within budget, and according to specification.
3 What is a Project?A project is a (temporary) sequence of unique, complex, and connected activities that have one goal or purpose and that must be completed by a specific time within budget, and according to specification.
4 SchedulingA schedule is the conversion of a project action plan into an operating timetableIt serves as the basis for monitoring and controlling project activitywork changes daily, so this is essentialWith the plan and budget, it is the major tool for the management of projectsmost scheduling is at the WBS level (tasks), not the work package levelonly the most critical work packages may be shown on schedule
5 SchedulingIn a project environment, the scheduling function is more important than it would be in an ongoing operationProjects lack the continuity of day-to-day operations and often present much more complex problems of coordination
6 SchedulingThe basic approach of all scheduling techniques is to form a network of activity and event relationshipsThis network graphically portrays the relations between a project’s tasksTasks that must precede or follow other tasks are then clearly identified, in time as well as function
7 Network Scheduling Advantages Networks are a powerful tool for planning and controlling a project and have the following benefits:consistent framework for planning, scheduling, monitoring, and controlling the projectillustrates the interdependence of all tasks, work packages, and work elementsdenotes the times when specific individuals must be available for work on a given task
8 Network Scheduling Advantages aids in ensuring that the proper communications take place between departments and functionsdetermines an expected project completion dateidentifies so-called critical activities that, if delayed, will delay the project completion timeidentifies activities with slack that can be delayed for specific periods without penalty
9 Network Scheduling Advantages determines the dates on which tasks may (or must) be started if the project is to stay on scheduleillustrates which tasks must be coordinated to avoid resource timing conflictsillustrates which tasks may (or must) run in parallel to achieve the predetermined project completion daterelieves some interpersonal conflict by clearly showing task dependencies
10 Network Scheduling Techniques PERT was developed in 1958 for the Polaris missile/submarine projectThe Critical Path Method (CPM) was developed by DuPont during the same time periodInitially, CPM and PERT were two different approachesCPM used deterministic time estimates and allowed project crunchingPERT used probabilistic time estimatesMicrosoft Project (and others) have blended CPM and PERT into one approach
11 TerminologyActivity - A specific task or set of tasks that are required by the project, use up resources, and take time to completeEvent - The result of completing one or more activities. An identifiable end state occurring at a particular time. Events use no resources.Network - The combination of all activities and events that define a projectDrawn left-to-rightConnections represent predecessors
12 Terminology Continued Path - A series of connected activitiesCritical - An activity, event, or path which, if delayed, will delay the completion of the projectCritical Path - The path through the project where, if any activity is delayed, the project is delayedThere is always a critical pathThere can be more than one critical path
13 Terminology Continued Sequential Activities - One activity must be completed before the next one can beginParallel Activities - The activities can take place at the same timeImmediate Predecessor – an activity that must be completed before a particular activity can beginAn activity can be in any of these conditions:It may have a successor(s) but no predecessor(s) - starts a networkIt may have a predecessor(s) but no successor(s) - ends a networkIt may have both predecessor(s) and successor(s) - in the middle of a network
14 Terminology Continued Activity on Arrow (AOA) - Arrows represent activities while nodes stand for eventsActivity on Node (AON) - Nodes stand for events and arrows show precedence
16 Constructing an AON Diagram Begin with the START activityAdd activities without predecessorsThere will always be oneThere may be more than one3. Add activities that have existing activities as predecessors4. Repeat step 3 until no more activities
17 Gantt Charts Developed by Henry L. Gantt in 1917 Shows planned and actual progressEasy-to-read method to show current status
18 Gantt Charts: Advantages and Disadvantages Easily understoodProvide a picture of the current state of a projectDifficult to follow with complex projects
21 Class Individual Exercise - 2. Create a new ProjectCreate the 12 Tasks from the previous slideenter their names and durationsenter the task dependenciesNow enter resources as follows:JasonJeff, EmilyEmilyJeffArielPatMarshaMarcSave your work!
22 The Work Breakdown Structure The Work Breakdown Structure (WBS) can take a variety of forms that serve a variety of purposesThe total program can be described as a summation of subdivided elements.Planning can be performed.Costs and budgets can be established.Time, cost, and performance can be tracked.Schedules and status-reporting procedures can be established. (=> Gantt chart)Responsibility for each element can be assigned.
24 The Work Breakdown Structure - 2 The WBS often appears as an outline with Level 1 tasks on the left and successive levels appropriately indentedThe WBS may picture a project subdivided into hierarchical units of tasks, subtasks, work packages, etc.
25 Most common type: Six-Level Indented Structure The Work Breakdown Structure - 3LEVELDESCRIPTION1Total ProgramUsually specified by the client and managed the project manager.2Project(s)3Task(s)4Subtask(s)Usually specified by the functional manager(s).5Work Package(s)6Level of EffortMost common type: Six-Level Indented Structure
28 The Work Breakdown Structure - 4 Summary: The WBS is an important document and can be tailored for use in a number of different waysIt may illustrate how each piece contributes to the project in terms of performance, responsibility, schedule, and budgetIt may list the vendors or subcontractors associated with specific tasksIt may serve as the basis for cost or schedule estimatesIt may be used to document that all parties have signed off on their various commitments to the project
29 The Work Breakdown Structure Steps for designing and using the WBS:Using the action plan, list the task breakdown in successively finer levels of detail. Continue until all meaningful tasks or work packages have been identified.For each such work package, identify the data relevant to the WBS: personnel and organizations responsible for each task.All work package information should be reviewed with the individuals or organizations who have responsibility for doing or supporting the work to verify the accuracy of the WBS
34 Critical Path and TimeNotation:[Task name, expected time, variance]
35 Critical Path Calculation To find the critical path:start with set of children of the Start nodefor each node: use the earliest start time (the greatest “earliest finish time of all this node’s predecessors), add in the duration to calculate the earliest finish timerepeat step 2 for the children of each node in the set
36 Slack Calculation To find the slack: start with End node and note its LS timefor each predecessor node: set the LF time to the lowest LS time of the successor(s) and subtract the duration to get the EF timerepeat step 2 for the children of each node in the set
41 Calculating Activity Times Notes:a is the optimistic estimateb is the pessimistic estimatem is an estimate of the modeTE is a calculation of the meanσ2 is the variance; a representation of the uncertaintyσ is the standard deviation
43 Uncertainty of Project Completion Time Assume activities are statistically independentis this reasonable?The variance of a set of activities is the sum of the individual variancesWe are most interested in variances along the critical path!
44 Fun With Statistics!What is the probability of completing a project on time, given a measure of variance and a critical path?We can answer that by calculating Z (# of standard deviations) as follows:Z = (D - ) /where D = desired project completion time= critical time of the project= variance of the critical path
45 Example ContinuedIf we want to complete the project in 50 days then D = 50, μ = 43, = 33
46 Example - 2.The likelihood of completing the project in 50 days is 88.88% (see Table next slide)If we want 95% certainty of on-time completion:D = μ + σ * Z= * = daysFor 99% certaintyD = * = days
48 Implications As D => μ, Z => 0 When Z = 0, probability of on-time completion is 50%Implication?If you want a high probability of being on time, you need some slack in the schedule!What about non-critical paths?Any path that has low slack and significant variance is a potential trouble spot.
49 Implications - 2. This is a great tool for you as a manager! Your boss will want estimates. What is your basis for making them? Guesses?
50 In Class Group Exercise Look at the WBS that you created for your project.From this, create a Gantt chart for your project.Determine the durations and dependencies for each of your project tasks.You only need to do “expected” duration for now.
51 In-class Group Exercise - 2 Calculate the total duration for your group project (and, hence, your critical path).Now, create a spreadsheet. For each project task, list:its optimistic, pessimistic, and expected durationsyou will have to do some educated guessing at this stage; that is normal
52 In-class Group Exercise - 3 Calculate TE, , and for each taskSave this in your spreadsheet.Note for the critical path
53 In-class Group Exercise - 4. Determine D for your project. Calculate Z.What is your probability of completing at time D?Submit your Gantt chart, your spreadsheet and an explanation of the WBS and the assumptions behind your estimates before next class.