Pert (CPM)

Complex projects require a series of activities, some of which must be performed sequentially and others that can be performed in parallel with other activities. This collection of series and parallel tasks can be modeled as a network.

In 1957 the Critical Path Method (CPM) was developed as a network model for project management. CPM is a deterministic method that uses a fixed time estimate for each activity. While CPM is easy to understand and use, it does not consider the time variations that can have a great impact on the completion time of a complex project.

The Program Evaluation and Review Technique (PERT) is a network model that allows for randomness in activity completion times. PERT was developed in the late 1950's for the U.S. Navy's Polaris project having thousands of contractors. It has the potential to reduce both the time and cost required to complete a project.

Gantt chart

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.

Although now regarded as a common charting technique, Gantt charts were considered revolutionary when they were introduced. In recognition of Henry Gantt's contributions, the Henry Laurence Gantt Medal is awarded for distinguished achievement in management and in community service. This chart is used also in Information Technology to represent data that has been collected.

Project management evaluation technique

A project is a finite endeavor--having specific start and completion dates--undertaken to meet particular goals and objectives, usually to bring about beneficial change or added value. This finite characteristic of projects stands in contrast to processes, or operations--which is repetitive, permanent or semi-permanent functional work to produce products or services. In practice, the management of these two systems is often found to be quite different, and as such requires the development of distinct technical skills and the adoption of separate management.


The primary challenge of project management is to achieve all of the project goals and objectives while honoring the preconceived project constraints. Typical constraints are scope, time and budget. The secondary—and more ambitious—challenge is to optimize the allocation and integration of inputs necessary to meet pre-defined objectives.

Work Breakdown

A work breakdown structure (WBS) in project management and systems engineering, is a tool used to define and group a project's discrete work elements (or tasks) in a way that helps organize and define the total work scope of the project.

A work breakdown structure element may be a product, data, a service, or any combination. A WBS also provides the necessary framework for detailed cost estimating and control along with providing guidance for schedule development and control. Additionally the WBS is a dynamic tool and can be revised and updated as needed by the project manager.


Overview

The Work Breakdown Structure is a tree structure, which shows a subdivision of effort required to achieve an objective; for example a program, project, and contract. In a project or contract, the WBS is developed by starting with :

* the end objective and
* successively subdividing it into manageable components
* in terms of size, duration, and responsibility (e.g., systems, subsystems, components, tasks, subtasks, and work packages)
* which include all steps necessary to achieve the objective.

The Work Breakdown Structure provides a common framework for the natural development of the overall planning and control of a contract and is the basis for dividing work into definable increments from which the statement of work can be developed and technical, schedule, cost, and labor hour reporting can be established.

A work breakdown structure permits summing of subordinate costs for tasks, materials, etc., into their successively higher level “parent” tasks, materials, etc. For each element of the work breakdown structure, a description of the task to be performed is generated. This technique (sometimes called a System Breakdown Structure ) is used to define and organize the total scope of a project.

The WBS is organized around the primary products of the project (or planned outcomes) instead of the work needed to produce the products (planned actions). Since the planned outcomes are the desired ends of the project, they form a relatively stable set of categories in which the costs of the planned actions needed to achieve them can be collected. A well-designed WBS makes it easy to assign each project activity to one and only one terminal element of the WBS. In addition to its function in cost accounting, the WBS also helps map requirements from one level of system specification to another, for example a requirements cross reference matrix mapping functional requirements to high level or low level design documents.

The S-Curve

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).