Anne-Marie
Mahfouf

    annma@kde.org

Raphael
Langerhorst

    raphael.langerhorst@kdemail.net

# Definitions

## Gantt charts

A Gantt chart is a popular type of bar chart, that aims to show the timing of tasks or activities as they occur over time. Although the Gantt chart did not initially indicate the relationships between tasks this has become more common in current usage as both timing and interdependencies between tasks can be identified.

In project management, a Gantt chart can show when the project terminal elements start and finish, summary elements (shown) or terminal element dependencies (not shown). A terminal element is defined as the smallest task tracked as part of the project effort. The tasks are displayed on a page as bars. The page is laid out such that time increases as you move across the page. A task's start time/date is indicated by the point on the page the bar starts, and it's duration is indicated by the length of the bar.

Since the initial introduction of Gantt charts, they have become an industry standard as a key project management tool for representing the phases, tasks and activities that are scheduled as part of a project Work Breakdown Structure (WBS) or timeline of tasks.

The initial format of the chart was developed by Henry L. Gantt (1861-1919) in 1910 (see Work, Wages and Profit by H. L. Gantt, published by The Engineering Magazine, NY, 1910).

## Work Breakdown Structure (WBS)

In project management, a work breakdown structure (WBS) is an exhaustive, hierarchical (from general to specific) tree structure of deliverables and tasks that need to be performed to complete a project.

The purpose of a WBS is to identify terminal elements (the actual items to be done in a project). Therefore, WBS serves as the basis for much of project planning.

A useful rule of thumb is that any project can be broken down into between 10 and 20 tasks.

Work breakdown structure is a very common project management tool. Many United States government statements of work require work breakdown structures.

See the section to learn how to configure your WBS.

## Float

Float in project management is the amount of time that a terminal element in a project network can be delayed by, without causing a delay to:

- subsequent terminal elements (free float)

- project completion date (total float).

Float is sometimes also called slack.

## Task

A task is a part of a project that needs to be accomplished within a defined period of time. Tasks can be linked together to create Dependencies.

Tasks take place over a period of time and generally consume resources.

A task is termed critical when it has zero or negative float.

In &kplato;, each task has a task ID, a name and a responsible person. The timing, the cost and the assigned resources can also be set in the Task Settingsdialog.

A subtask is any node in the WBS tree that has a task as its parent.

## Resource

A resource is an item required to complete a task. Resources can be people, equipment, facilities, funding or anything else needed to perform the work of a project. Resources can have a limited time availability (&ie; an employee that works 8 hours a day, 5 days a week).

The availability is defined by calendars.

In &kplato; resources are either persons (work) or machines/devices (material).

## Calendars

A calendar defines at what time a resource is available.

Calendars can be either a regular working week or special working times that can be individually defined for each day. This allows for very subtle control over the availability of resources.

Every resource is usually connected to a calendar.

In &kplato; you can even use hierarchical calendars.

## Milestone

A milestone is a scheduled event signifying the completion of a major deliverable or a set of related deliverables (usually marking the end of a period). A milestone is an activity with zero duration and no effort &ie; there is no work associated with a milestone. It is a flag in the workplan to signify some other work has completed.

Usually a milestone is used as a project checkpoint to validate how the project is progressing and revalidate work. Milestones are also used as high-level snapshots for management to validate the progress of the project. In many cases there is a decision to be made at a milestone.

## Critical path

A path is a series of connected tasks. In project management, a critical path is the sequence of project network terminal elements with the longest overall duration, determining the shortest time to complete the project.

The duration of the critical path determines the duration of the entire project. Any delay of a terminal element on the critical path directly impacts the planned project completion date (i.e. there is no float on the critical path). For example, if a task on the critical path is delayed by one day, then the entire project will be delayed by one day (unless another task on the critical path can be accelerated by one day).

A project can have several, parallel critical paths. An additional parallel path through the network with the total duration just shorter than the critical path is called a sub-critical path.

Originally, the critical path method considered only logical dependencies among terminal elements. A related concept is the critical chain, which adds resource dependencies.

The critical path method was invented by the DuPont corporation.

## Scheduling

Scheduling is the process of creating a project schedule based on the project data like tasks, resources and calendars. The result can be viewed in a chart, like a gantt chart. &kplato; can also generate reports for a project.

There are usually various scheduling modes, like optimistic, expected and pessimistic scheduling. When creating a task the additional estimation percentage for optimistic and pessimistic scheduling can be set. These settings are then used for the various scheduling modes.

When scheduling a project with &kplato;, you can choose between optimistic, expected and pessimistic scheduling.