SCHEDULE CREATION AND ANALYSIS. 1 Powered by POeT Solvers Limited

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1 SCHEDULE CREATION AND ANALYSIS 1 Powered by POeT Solvers Limited

2 While building the project schedule, we need to consider all risk factors, assumptions and constraints imposed on the project to be able to achieve a realistic schedule. The activity durations and the activity sequence determine the overall project schedule. Inputs Tools and techniques Outputs Activity list Activity attributes Activity resource requirements Project schedule network diagrams Resource calendars Activity duration estimates Project scope statement Enterprise environmental factors Organizational process assets Schedule network analysis Critical path method Critical chain method Resource levelling What-if scenario analysis Applying leads and lags Schedule compression Scheduling tool Project schedule Schedule baseline Schedule data Project document updates 2 Powered by POeT Solvers Limited

3 Develop Schedule Inputs DEVELOP SCHEDULE Activity List: Please refer to the Define Activities Outputs section. Activity Attributes: Please refer to the Define Activities Outputs section. Project Schedule Network Diagram: Please refer to the Sequence Activities Outputs section. Activity Resource Requirements: Please refer to the Estimate Activity Resources Outputs section. Resource Calendars: Please refer to the Estimate Activity Resources Inputs section. 3 Powered by POeT Solvers Limited

4 Activity Duration Estimates: Please refer to the Estimate Activity Resources Outputs section. Project Scope Statement: Please refer to the Define Scope Outputs section. Enterprise Environmental Factors: Many organizations may have automated the scheduling process by employment of some scheduling tool. This will influence the Develop Schedule process. Organizational Process Assets: Some of the organizational process assets that will influence the Develop Schedule process include Scheduling methodology and Project calendar. 4 Powered by POeT Solvers Limited

5 Develop Schedule Tools and Techniques Schedule Network Analysis: This is a technique that generates the project management schedule. It is a detailed report of how and when you execute the next step of your project. Another technique is Monte Carlo Analysis. In this method of estimating, a computer is used to simulate the outcome of the project, making use of the three point estimates. The three point estimates are optimistic, pessimistic and most likely estimate. Program Evaluation and Review Technique (PERT): This is a model for project management designed to analyse and represent the tasks involved in completing a given project. For each activity the three point estimate is taken using the following formula 5 Powered by POeT Solvers Limited

6 t e = t o + 4t m + t p 6 Where t e is the Expected time, t o is the Optimistic time, t m is the most probable activity time and t p is the Pessimistic time. The Standard Deviation, which is a good measure of the variability of each activity is calculated by the formula: s = t p t 0 6 The Variance is the square of the Standard Deviation. 6 Powered by POeT Solvers Limited

7 For example, if the estimated duration for task A is determined as 3 days (Optimistic estimate), 5 days (Most likely estimate) and 7 days (Pessimistic estimate), then using PERT, the duration for activity A is estimated as follows: t e = ( ) / 6 = 30 / 6 = 5 days The standard deviation for this activity (SD) = (7 3) / 6 = 4 / 6 = 0.66 The variation for this activity = = 0.44 which means that task A can be completed between (5 0.44) and ( ) days i.e. the task A can be completed between 4.56 and 5.44 days. 7 Powered by POeT Solvers Limited

8 Critical Path Method (CPM): This is a mathematically based algorithm for scheduling a set of project activities. It determines the minimum total project duration and the earliest possible finish date of the project as well as the amount of scheduling flexibility (total float) in the schedule model. CPM involves the following steps: 1. Identify the specific activities and milestones. 2. Determine the proper sequence of the activities. 3. Construct a network diagram. 4. Ensure that all activities on the activity list are included in the diagram. 5. Ensure that all precedence relationships are correctly indicated by arrows going from the predecessor activities to the successor activities. 6. Ensure that any known lags or leads are indicated on the diagram. 7. Estimate the time required for each activity. 8. Determine the critical path. 9. Update the CPM chart as the project progresses. 8 Powered by POeT Solvers Limited

9 Let us take an example of purchasing a car as our project. As the first step, we need to identify the specific activities and the milestones. Task Description Duration (in Predecessor days) activity) A Decide on possible models meeting our 2 - requirements B Investigate vendors and their quality of 3 A service C Visit each vendor and test drive each model 5 B available D Select the model and vendor for purchase 2 C E Investigate financing options with different 5 A banks F Select best financing option and bank 2 E G Apply for a loan from the selected bank 7 D,F H Buy new car 1 G (Preceding 9 Powered by POeT Solvers Limited

10 The next step is to construct the network diagram using the information above. D is the duration and arrows indicate precedence. A D = 2 B D = 3 C D = 5 D D = 2 Start H D = 1 End E D = 5 F D = 2 G D = 7 Figure 1: Network Diagram 10 Powered by POeT Solvers Limited

11 Network Rules and Computation: Three rules are applied to all networks in order to compute network start and finish times. Rule 1: Before a task can begin, all tasks preceding it must be completed. Rule 2: Arrows denote which tasks come first. Rule 3: When two or more activities precede another activity, the earliest time that the final activity can be started is the larger of the durations of the activities preceding it. To clarify what these rules mean, let us examine the boxes in the network diagram below used to calculate the schedule. D stands for duration of the task, ES stands for Earliest Start i.e. the earliest time the task can begin, given all preceding tasks are completed and EF stands for Earliest finish i.e. the earliest time the task can finish, given the completion of all preceding tasks and the task itself (EF = ES + D) Powered by POeT Solvers Limited

12 Path A A ES = 0 EF = 2 D = 2 B ES = 2 EF = 5 D = 3 C ES = 5 EF = 10 D = 5 D ES = 10 EF = 12 D = 2 Start H ES = 14 EF = 15 D = 1 End E ES = 0 EF = 5 D = 5 F ES = 5 EF = 7 D = 2 G ES = 7 EF = 14 D = 7 Path B Figure 2: Network Diagram showing early start and finish durations Powered by POeT Solvers Limited

13 From the diagram, when calculating the early start for activity H, we need to consider both the possible paths, Path A and Path B. As activity H cannot start before activities D and G are complete, it can start only after day 14 i.e. in this example, buying a car can be done after day 14. As the longest duration to complete the project is Path B, it is the crucial path for this project. Any delay on any activity on the critical path would lead to the project being delayed. Computing the early start and early finish in the method described above is known as the Forward pass. Late Start (LS) and Late Finish (LF) use the Backward pass technique. You can think of backward pass as calculating backward to see how much an activity may slide without affecting the finish date Powered by POeT Solvers Limited

14 Late Start (LS) is the latest time an activity may begin without delaying the project duration. Late Finish (LF) is the latest time an activity may be completed without delaying teh project duration. This is done by starting at the End activity and finishing at the Start activity. Late start = Late finish Duration The Float or Slack is determined by substracting the ES from the LS or the EF from the LF. Activities having a float of zero are activities that are on the critical path. Precedence diagramming method (PDM): PDM is a visual representation that depicts the activities involved in a project and is also known as project network diagrams. The PDM places activities on nodes with arrows linking activities. Activity nodes contain information about duration, costs, resources, and constraints Powered by POeT Solvers Limited

15 In PDM, a work item can be connected from either its start or its finish. This allows a start-to-finish logic presentation with no need to break the work time down. Another characteristic of PDM diagrams is the use of lead and lag components. The PDM is also called Activity on Node (AON) diagramming method. There are four types of relationships between predecessor activities and successor activities. They are: Finish to Start (FS) Finish to Finish (FF) Start to Start (SS) Start to Finish (SF) 15 Powered by POeT Solvers Limited

16 Finish to Start (FS): This means the successor activity cannot start until its predecessor has been completed. Finish to Finish (FF): This means the successor activity cannot be completed before its predecessor has been completed. Start to Start (SS): This means that the successor activity cannot start until its predecessor has started. Start to Finish (SF): This means the successor activity cannot be finished before its predecessor starts. These relationships can also have time durations associated with them. In PDM, the finish to start relationship is more commonly used and start to finish is rarely used Powered by POeT Solvers Limited

17 Critical Chain Method: The critical chain method is developed from the CPM approach and considers the effects of resource allocation, resource levelling, and activity duration uncertainty on the CPM-determined critical path. The critical chain method introduces the concept of buffers and buffer management. Three types of buffers are feeding buffers, resource buffers, and project buffers. Project Buffers: A project buffer is inserted at the end of the project network between the last task and the completion date. Any delays on the longest chain of dependent tasks will consume some of the buffer but will leave the completion date unchanged and so protect the project Powered by POeT Solvers Limited

18 Feeding Buffers: Delays on paths of tasks feeding into the longest chain can impact the project by delaying a subsequent task on the Critical Chain. To protect against this, feeding buffers are inserted between the last task on a feeding path and the Critical chain. Resource Buffers: These buffers can be set alongside of the Critical chain to ensure that the appropriate people and skills are available to work on the Critical chain tasks as soon as needed. The longest resource-levelled path through the schedule, including buffers, is the critical chain. The defining factors in the critical chain method are buffer activities and resource levelling Powered by POeT Solvers Limited

19 Task A Task B Critical Path Method Task C Task D Task A Task B Task C Critical Chain Method Task D Figure 3: A Critical Chain Buffer 19 Powered by POeT Solvers Limited

20 Critical chain differs from Critical path method in four main aspects: 1. The realization that no matter how good risk management is, significant unexpected risks which where unforeseen in the risk management phase, will materialize during a project and will necessitate reaction. 2. The focus of managerial attention the critical chain, will remain quite fixed throughout the project. 3. The resource contention has such a magnitude in today s lean organizational structures that the duration of projects is dependent on resource availability to no lesser degree than on the logical sequence of activities. 4. In CPM, a significant margin is contained in all activities, but when exposed and aggregated (instead of being distributed and hidden in individual activities), its risk absorption will be greater by orders of magnitude compared to its current situation Powered by POeT Solvers Limited

21 Monte Carlo Method: This is a class of algorithms that rely on repeated random sampling to compute their results. It tends to be used when it is infeasible or impossible to compute an exact result with a deterministic algorithm. There is no single Monte Carlo method; instead, the term describes a large and widely-used class of approaches. However, these approaches tend to follow a particular pattern: 1. Define a domain of possible inputs. 2. Generate inputs randomly from the domain. 3. Perform a deterministic computation using the inputs. 4. Aggregate the results of the individual computations into the final result Powered by POeT Solvers Limited

22 Resource levelling: This is the process of ensuring that resources are being used optimally in a project. The project manager should ensure that resources are not under-utilized or over-utilized. Schedule Compression Techniques: This is the shortening of the project schedule without affecting the project scope. There are two main techniques for shortening the project schedule namely: 1. Project crashing and 2. Project fast tracking. Project Crashing: Crashing the schedule means deploying additional resources to the critical path activities to reduce the schedule duration. Adding resources can include approving overtime, bringing additional resources or paying extra to expedite the delivery of activities in the critical path Powered by POeT Solvers Limited

23 Crashing generally results in increased costs. The cost and schedule trade-offs have to be analyzed to obtain greatest amount of compression for the least amount of incremental cost. Steps in crashing a project Determine if the critical path (CP) falls within the targeted time. If yes, stop. If no, compute crash cost per time period for each activity. Select activity on CP with lowest crash cost and crash the project. Re-compute CP and check to see if it is within the targeted time. Repeat as necessary. Project Fast Tracking: Fast tracking is done by overlapping or compressing some of the project activities phases. This will result in overall shorter project schedule. This means doing some or several activities or phases in parallel Powered by POeT Solvers Limited

24 The disadvantage of project fast tracking is that it increases risk and potentially causes rework as it requires more management effort to track several activities or phases in parallel. Develop Schedule Outputs Project Schedule: In a project schedule, the project activities are shown in a logical sequence with the start date, finish date and the duration for each activity. The duration of all the activities adds up to the project duration. The project schedule can be presented in tabular form or in graphical form using milestone charts, bar charts or project schedule network diagram Powered by POeT Solvers Limited

25 Project Schedule Network Diagram: This diagram will have the information such as the activity start and finish dates, the network logic and the critical path schedule activities. The network diagram will be represented by using an activity on node (AON) diagramming format. The project schedule network diagram is also called a logical bar chart. Schedule Baseline: A schedule baseline is a specific version of the project schedule developed from the schedule network analysis, which is accepted and approved by the project management team as the schedule baseline. In other words, the schedule baseline is the finalized version of the schedule which has been approved by the stakeholders. It is used to track and compare the actual progress of tasks during execution of the project Powered by POeT Solvers Limited

26 SUMMARY Project time management is a very improtant skill for a successful project manager. It is observed that poor schedule management is one of the major causes for project cost overrun. To have a better time management in a project, the project manager has to list out what all the activities to be accomplished, the logical sequence in which they have to be performed, the resources required to accomplish each activity and how long they will take. All these information are required to develop a realistic projec schedule. Once the schedule is developed, the project manager has to effectively monitor and control the execution, by employing EVM (Earned Value Management) techniques. Any variance has to be analysed and if required, corrective or preventive actions are taken to bring the project back on track Powered by POeT Solvers Limited

Project Management Professional (PMP) Exam Prep Course 06 - Project Time Management

Project Management Professional (PMP) Exam Prep Course 06 - Project Time Management Slide 1 Looking Glass Development, LLC (303) 663-5402 / (888) 338-7447 4610 S. Ulster St. #150 Denver, CO 80237 information@lookingglassdev.com