Gantt chart

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"Gantt" redirects here. For other uses, see Gantt (disambiguation).

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

A Gantt chart is a popular 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 (also called "TIME NOW"), as shown here.

[edit] Historical development

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).

In the 1980s, personal computers eased the creation and editing of elaborate Gantt charts. These desktop applications were primarily intended for project managers and project schedulers. In the late 1990s and early 2000s, Gantt charts became a common feature of web-based applications, including collaborative groupware.

Although now considered a common charting technique, Gantt charts were considered quite revolutionary at the time they were introduced. In recognition of Henry Gantt's contributions, the Henry Laurence Gantt medal is awarded for distinguished achievement in management and service to the community.

[edit] Advantages and limitations

Gantt charts have become a common technique for representing the phases and activities of a project work breakdown structure, so they can be understood by a wide audience.

A Gantt chart is easily comprehended for small projects that fit on a single sheet or screen, but they can become quite unwieldy for projects with more than about 30 activities. Larger Gantt charts may not be suitable for most computer displays. A related criticism is that Gantt charts communicate relatively little information per unit area of display. That is, projects are often considerably more complex than can be communicated effectively with a Gantt chart.

Gantt charts only represent part of the triple constraints of projects (see project management for discussion of the triple constraints), because they focus primarily on schedule management.

Although project management software can show schedule dependencies as lines between activities, displaying a large number of dependencies may result in a cluttered or unreadable chart.

Because the horizontal bars of a Gantt chart have a fixed height, they can misrepresent the planned workload (resource requirements) of a project. In the example shown in this article, Activities E and G appear to be the same size, but in reality they may be orders of magnitude different. A related criticism is that all activities of a Gantt chart show planned workload as constant. In practice, many activities (especially summary elements) have front-loaded or back-loaded work plans, so a Gantt chart with percent-complete shading may actually miscommunicate the true schedule performance status.

[edit] External links – Instructional

• Long-running discussion regarding limitations of the Gantt chart format, and alternatives, on Edward Tufte's website
• Project schedule from University of Washington's project management site
• Project schedule from Applied Software Project Management (O'Reilly)

[edit] External links – Software

• DlhSoft Project Management Control Library Project Management Control Library (for developing gantt-chart enabled Windows Forms applications on .NET 2.0)
• www.xleasygantt.com - Free Excel Gantt Chart Creation Template with automatic calendar creation, add and remove tasks, level indenting and date picker.
• DlhSoft Project Manager 2006 Gantt-chart enabled project management software
• GanttPV Project scheduling software (scriptable, cross-platform, and open source)
• The Gantt Project, an open source computer program (as a Java Webstart or an Application program) for the creation of Gantt charts
• GTD-Manager, a Java program for visualizing project plans/progression using Gantt and Date Drift Charts
• The R programming language can produce Gantt charts via the plotrix package. It is shown in the R Graph Gallery.
• Open Workbench, open-source project scheduling software for Windows
• TaskJuggler, open source project management application that was designed to handle large, fast moving projects with many tasks and resources
• AnyChart Gantt, Flash component for creating Gantt Charts
• JPACE, A freely available project management WBS, schedule, and Gantt chart in MS Project
• jxProject A Java-based, ad-supported software for creating Gantt and Resource Charts.
• Gnome Planner Free Software for planning, optional with PostgreSQL interface.
• Excel Spreadsheets High quality free Excel spreadsheets for Gantt project management.
• SmartDraw