Tools used by the Project Manager for Project Planning

Tools used by the Project Manager for Project Planning


Published on April 19, 2013


Network Diagrams

Network diagrams are one of the tools used by the project manager for project planning. It is also sometimes referred to as an “Arrow” diagram because it uses arrows to connect activities and represent precedence and interdependencies between activities of a project.

There are some assumptions that need to be made while forming the Network Diagram. The first assumption is that before a new activity begins, all pending activities should have been completed. The second assumption is that all arrows indicate logical precedence. This means that the direction of the arrow represents the sequence that activities need to follow. The last assumption is that a network diagram must start from a single event and end with a single event. There cannot be multiple start and end points to the network diagram.

In order for the network diagram to calculate the total duration of the project, the project manager needs to define four dates for each task.

The first two dates relate to the date by when the task can be started. The first date is Early Start – this the earliest date by when the task can be started. The second date is Late Start – this is the last date by when the task should start.

The second two dates relate to the dates when the task is complete. Early Finish is the earliest date by when the task can be completed. Late Finish is the last date by when the task should be completed. The Duration of the task is calculated as the difference between the Early Start and Early Finish of the task. The difference between the Early Start and Late Start of the task is called the slack time available for the task. Slack can also be calculated as the difference between the Early Finish and Late Finish dates of the task. Slack time for a task is the amount of time the task can be delayed before it causes a delay in the overall project timeline.

Critical Path Method

Critical Path method also known as CPM is an important tool used by Project Managers to monitor the progress of the project to ensure that the project is on schedule. The Critical Path for a project is the longest sequence of activities on the network diagram and is characterized by zero slack for all activities on the sequence. This means that a smallest delay in any of the activities on the critical path will cause a delay in the overall timeline of the project. This makes it very important for the project manager to closely monitor the activities on the critical path and ensure that the activities go smoothly. If needed, the project manager can divert resources from other activities that are not on the critical path to activities on the critical path to ensure that the project is not delayed. When a project manager removes resources from such activities, he needs to ensure that the activity does not become a critical path activity because of the reduced number of resources.

During the execution of the project the critical path can easily shift because of multiple factors and hence needs to be constantly monitored by the project manager. A complex project can also have multiple critical paths at the same.

The critical path in the network diagram is highlighted in orange. Notice that all activities on this path have zero slack.

Program (or Project) Evaluation and Review Technique

The Program (or Project) Evaluation and Review Technique, commonly abbreviated as PERT (pronounced as PERT), is a form of the Network Diagram as discussed earlier. PERT is also used for identifying the critical path for the project. This technique was developed to simplify the planning and scheduling of large and complex projects and creating more realistic estimates towards the duration of each activity. While the standard Network Diagram uses one estimate for duration of each activity, PERT involves three kinds of estimates for each activity.

The first estimate is an optimistic estimate represented as to (pronounced as T-O). The optimistic estimate considers all factors that affect the activity to go in favor of the activity. For example, optimistic estimates will assume that no issues are encountered during the activity and all resources perform at their highest efficiency levels. Optimistic estimates are therefore slightly less than other estimates. The second estimate is called the “most likely” estimate and is represented as tm (pronounced as T-M). This estimate assumes that the activity will encounter some issues during execution and hence provides for some contingency buffers in the estimate. The third estimate is the “pessimistic” estimate and is represented as tp (pronounced as T-P). This estimate assumes that whatever that can go wrong during the execution of the activity, will go wrong. This estimate therefore includes large contingency buffers and is the highest amongst all the three estimates.

The realistic estimate for the activity is represented as te (pronounced as T-E) and is calculated by taking an average of all the three estimates. While calculating the average the “most likely” estimate is assigned a weightage of 4 whereas the other two estimates are treated as is.

The final realistic estimate calculated using PERT takes much more time to calculate but is much more realistic than estimates calculated without PERT.

In this PERT network chart, activities A, B, C and D, E, F are done in parallel as they are not dependent on each other. The duration of each activity is calculated using the PERT method. As has been mentioned in the key, the number below any activity is the time required to complete that activity. This time is in weeks.

Gantt Chart

Developed by Henry Laurence Gantt in 1910, the Gantt Chart provides a graphic schedule for planning and controlling the project and recording progress towards completion of various activities in the project. It represents project schedule as bar charts spread out over a timeline. Progress of each activity is indicated in a separate color from the planned duration of the activity. The difference in colors and the length of the bar chart helps project managers identify delays, or schedule overruns in the project. For example, in this Gantt Chart you can see that activity A and Activity B were completed on time. However, Activity D seems to be running late and is expected to have a schedule overrun of about 1 day. This schedule overrun will also impact activity F and it will also finish about 1 day late.

This chart also depicts another way of representing Critical Path for a project. You can see that activities C and E have slack associated with them and hence are not on the critical path. On the other hand, activities B, D and F do not have any slack and are interdependent on each other thereby creating the Critical Path for the project. The chart also shows that activity B and activity C will start only after completion of activity A. Activity D will start after completion of activity B and activity E will start only after completion of activity C. Gantt chart helps in representing large amount of information in a compact graphical form.

Work Breakdown Structure

Work Breakdown Structure is the last project management tool discussed as part of this session. Though there are many more project management tools available, the ones discussed in this session are the ones which are most commonly judged in the ASQ CSSGB exam.

A Work breakdown structure, also called WBS, is a delivery oriented hierarchical decomposition of work. It is often used to define the total scope for the project and to identify required deliverables for the project. Having detailed project deliverables enables all stakeholders to get a common understanding on the project scope. Each team knows exactly what needs to be developed.

WBS divides each project deliverables and project work into smaller more manageable components. Items at the lowest level of the WBS are called Work Packages. A work package can be scheduled, cost estimated, monitored and controlled individually. Breaking up a large project into smaller work packages enables the project to be better planned, tracked and managed.

For example, in a project to develop a Telephone, a WBS will be used to break down the components of the telephone into smaller components, till each component can be individually assigned, estimated and developed. The final list of the components as derived by the WBS will also indicate the features that the phone will support. Anything that is not listed in the WBS will not be a part of the final product, in this case the telephone.

Project Documentation

After reviewing few important Project Management tools, we will now understand key elements of Project Documentation. Project Documentation refers to creating documents providing more details about the project. Such documents are used to gain better understanding of the project, preventing and resolving conflict between stakeholders, and sharing plans and status for the project. Documentation of a project is critical throughout all the phases of the project. Some of the benefits achieved through project documentation are mentioned below.

Documentation serves as a written proof for execution of the project. It helps teams achieve a common understanding of the requirements of the project and the status of the project. It removes personal bias as there is a documented history of discussions and decisions made for the project.

Depending on the nature of the project, each project produces a number of different documents. Some of these documents include Project Charter, Project Plan and its subsidiary plans which have been discussed in the earlier slides.

Other examples of project documentation include Project Status reports including Key Milestones Report, Risks items and pending action items. The frequency of these reports is determined by the need and complexity of the project. These reports are sent to all stakeholders to keep them abreast of the status of the project. Another example of project documentation is the Final Project Report. This report is prepared at the end of the project and includes a summary of the complete project.

Vehicles for Project Documentation

Some more examples of Project Documentation include Project Storyboard, inputs generated from Statistical tools, outputs from spreadsheets, checklists and other miscellaneous documents.

A Project storyboard is a template provided by an organization to formally document the progress of the Six Sigma project. These are also used in review meetings with various stakeholders of the project to review progress of the project. Statistical tool outputs are generated from statistical tools like SPSS which stands for Statistical Package for Social Sciences or Minitab. These are very useful in the Analyze and Measure phase of a six sigma project.

Output from spreadsheets are statistical calculations or graphs as used in Microsoft Excel Sheet or Open Office. Checklists are often used at the end of each Six Sigma phase to ensure the required steps, tools and techniques have been followed as part of the project.

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About the Author

Chandana is working as a Senior Content Writer in and handles variety of creative writing jobs. She has done M.A. in English Literature from Gauhati University. A PRINCE2 Foundation certified, she has a unique and refreshing style of writing which can engross the readers to devour each sentence of her write-ups.


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