Saturday, July 4, 2009

Gantt Chart


A Gantt chart showing three kinds of schedule dependencies (in red) and percent complete indications.

A Gantt chart is a type of bar chart that illustrates a project schedule. Gantt charts illustrate the start and finish dates of the terminal elements and summary elements of a project. Terminal elements and summary elements comprise the work breakdown structure of the project. Some Gantt charts also show the dependency (i.e, precedence network) relationships between activities. Gantt charts can be used to show current schedule status using percent-complete shadings and a vertical "TODAY" line as shown here.


Wednesday, July 1, 2009

S-Curve


Sample project s Curve


An S-Curve is a sigmoid function, that is a mathematical process or function that results in a S shaped curve also called a Sigmoid Curve. The S-Curve is used in project management as a means of representing the various expenditures of resources over the projected time of the project or as a means of charting the real-time expenditure of resources. This is important to project management in that it can be used to monitor the project as is progresses and compare it to the projected S-Curve to determine whether or the project is being completed within the time and budget limitations. These resources might be the cumulative cost of the project, the number of man hours required at any given stage in the project, the expenditure of raw materials for construction or assembly, etc.

The term S-Curve can also be used to indicate an S shaped chart resulting from a cumulative likelihood distribution. In this function, an S-Curve is a tool of quantitative risk analysis which project management would use to determine the possible dangers of any given course of action.

This term is defined in the 3rd and the 4th edition of the PMBOK.



The S Curve is a well known project management tool and it consists in "a display of cumulative costs, labour hours or other quantities plotted against time".The name derives from the S-like shape of the curve, flatter at the beginning and end and steeper in the middle, because this is the way most of the projects look like.

The S curve can be considered as an indicator and it's used for many applications related to project management such as: target, baseline, cost, time etc. That's why there is a variety of S Curves such as:
-Cost versus Time S Curve;(appropriate for projects that contain labour and non-labour tasks).
-Target S Curve;(This S Curve reflects the ideal progress of the project if all tasks are completed as currently scheduled)
-Value and Percentage S Curves;(Percentage S Curves are useful for calculating the project's actual percentage complete)
-Actual S Curve;(This S Curve reflects the actual progress of the project to date)

In order to be able to generate a S Curve, A Baseline and Production Schedule are necessary because they contain important information for each task: -the Baseline - contains information about Actual Start date and finish date.
-The Baseline - can also contain information about Man Hours and costs.
-The Production Schedule contains information about the actual percentage complete.

There are some software scheduling packages that generate automatically S Curves. For example MS Project does not have this possibility so a third party software application is needed to process the Baseline and Production Schedule data and generate the needed S Curve.( for example S Curve Generator that integrates with MS EXcel to generate S Curves).


Critical Path Method

The Critical Path Method, abbreviated CPM, or Critical Path Analysis, is a mathematically based algorithm for scheduling a set of project activities. It is an important tool for effective project management.

It was developed in the 1950s by the Dupont Corporation at about the same time that General Dynamics and the US Navy were developing the Program Evaluation and Review Technique (PERT)[1] Today, it is commonly used with all forms of projects, including construction, software development, research projects, product development, engineering, and plant maintenance, among others. Any project with interdependent activities can apply this method of scheduling.

The essential technique for using CPM is to construct a model of the project that includes the following:

  1. A list of all activities required to complete the project (also known as Work breakdown structure),
  2. The time (duration) that each activity will take to completion, and
  3. The dependencies between the activities.

Using these values, CPM calculates the longest path of planned activities to the end of the project, and the earliest and latest that each activity can start and finish without making the project longer. This process determines which activities are "critical" (i.e., on the longest path) and which have "total float" (i.e., can be delayed without making the project longer). In project management, a critical path is the sequence of project network activities which add up to the longest overall duration. This determines the shortest time possible to complete the project. Any delay of an activity on the critical path directly impacts the planned project completion date (i.e. there is no float on the critical path). A project can have several, parallel, near critical paths. An additional parallel path through the network with the total durations shorter than the critical path is called a sub-critical or non-critical path.

These results allow managers to prioritize activities for the effective management of project completion, and to shorten the planned critical path of a project by pruning critical path activities, by "fast tracking" (i.e., performing more activities in parallel), and/or by "crashing the critical path" (i.e., shortening the durations of critical path activities by adding resources).

Word Breakdown Structure

WBS Format for System Development Projects



Work Breakdown Structure - (WBS) A division of a project into tasks and subtasks. The tasks are numbered to indicate their relationship to each other. WBSs are indespensible for project planning, particularly when estimating time and resource requirements. Some industries use established work breakdown structure systems for billing and reporting purposes.

A Work Breakdown Structure is a results-oriented family tree that captures all the work of a project in an organized way. It is often portrayed graphically as a hierarchical tree, however, it can also be a tabular list of "element" categories and tasks or the indented task list that appears in your Gantt chart schedule. As a very simple example, Figure 1 shows a WBS for a hypothetical banquet.