Just as the project manager must evaluate alignment, benefits, and risks as well as other business and project factors when considering projects to manage, the project manager must also routinely make critical chart choices. During the course of a project, the project manager must assess whether GANTT charts, critical path analysis, task tracking, time capture, Program Evaluation and Review Technique (PERT) or another type chart will best serve to compute the estimate for the project's completion. In the book, Project portfolio management: a practical guide to selecting projects, managing portfolios, and maximizing benefits, Levine (2005), a project management specialist and consultant since 1962, asserts that tactical management systems range from the management of individual projects to the management of programs packed with projects, and may ultimately ascend to the management of asset allocation criteria that numerous initiatives, programs and projects support. During the paper, the writer relates historical and contemporary information regarding Gantt and PERT, two tactical tools regularly used to help manage projects as well as shares considerations to help one evaluate a number of similar chart tools.
History of Gantt Charts
Renditions of the history of the Gantt chart vary. In the book, An introduction to the history of project management, Chiu (2010) names Henri Fayol (1841- 1925) and Henry Gantt (1861-1919) as the forefathers of 20th century project management. In 1916, Fayol published the book, Administration Industrielle et Generale, which describes five primary management functions which ultimately comprises the basis of project management. "The five primary functions of management that he specified are planning, organizing, commanding, coordinating, and controlling" (Chiu, p. 4). Fayol's theory established a stronger scientific foundation for contemporary project management. As Gantt extended Fayol's theory, he reportedly developed the Gantt chart during 1917; with the ensuing charts and diagrams permitting processes to be charted and controlled. According to Chiu:
An example of their [Gantt chart's] application occurred during the First World War in constructing ships for the U.S. Navy. Gantt documented and analyzed the ship building process step-by-step, which enabled him to assess and provide data about how the management functions outlined by Fayol interrelated. Gantt charts have remained a significant aid in project management . . .. They have been used for major government projects, including in the construction of the Hoover Dam (1931- 1936) and the U.S. interstate highway system . . .. As a project management tool, their impact has been and continues to be immense. (Chiu, 2010, p. 4).
Chiu (2010) reports that both Fayol and Gantt studied and drew inspiration from the theories Frederick Winslow Taylor (1856-1915), presented in his text Scientific Management, to develop the Gantt chart. The Web publication, "What is a Gantt chart? (2010), however, asserts that Karol Adamiecki, a Polish engineer who managed a steelworks in southern Poland; with interest in management ideas and technique, devised the Gantt chart prototype in the mid 1890s. This source contends that approximately 15 years after Adamiecki, Gantt devised his personal version of the chart which then became popular in western countries. This led to the name Gantt being associated with this type of charts. In time, with the advent of computers and project management software, Gantt charts which were once laboriously prepared and updated by hand; came to be easily created, updated and printed.
Men Who Reportedly Created Gantt Chart (
What is a Gantt chart,
The Gantt chart depicts one of the oldest techniques manufacturing and service organizations routinely utilize for the controlling, planning, and of projects. In the book, Prod & Oper Mgmt,2E, Saxena (2009) explains that the Gantt chart, also known as a "bar chart" graphically represents "of a series of activities drawn to a time scale. Horizontal axis (K-axis) represents time and vertical axis (V-axis) shows the activities to be performed. The Gantt chart shows activities to specific jobs at individual/work centers by horizontal bars" (p. 175). The horizontal bar's position and length depict the designated activity's start and completion date of the activity.
Although the project manager initially prepares a Gantt chart for planning purposes, the chart also depicts the actual performance or progress as the project progresses. This presents a clear picture if/when any variations from the planned time occur. The Gantt chart also gives a comparison between the initial planned time and actual time it takes to complete a particular activity and/or project (Saxena, 2009).
In addition to portraying the projected time for each task in a project and how far each task has progressed, a Gantt chart, a horizontal bar chart, relates sequential and simultaneous tasks. The project manager can also quickly recount which tasks overlap in some way. In the book, System analysis and design, Dennis, Wixom, and Roth (2008) assert that the Gantt chart "can communicate the high-level status of a project much faster and easier than the work plan. Creating a Gantt chart is simple and can be done with a spreadsheet package, graphics, soft-ware (e.g., Microsoft VISIO), or a project management package. A Gantt chart like the quote at the start of this paper portrays reveals identical task information the project work plan contains, albeit, in a graphical manner. During the first step of creating a Gantt chart, the individual lists the tasks as rows in the chart. Based on the needs of the project, the project manager lists time across the top in increments. The project manager may divide a short project into hours or days, albeit, the project manager may segment a medium-sized project in weeks or months. The beginning of the horizontal bars, drawn to depict the start of each task, encompass the duration of each task and extend to mark exactly when the task will end. As individuals work on the various tasks, the project manager proportionately fills in the appropriate bars to designate how much of the task has been completed. The position of the filling to a vertical line drawn from a particular date proffers the project manager a picture of whether tasks are ahead of schedule, on time, or behind schedule. When a bar "is not filled in and appears to the left of the line, that task is behind schedule" (p. 90). A bar filled to the right of the line indicates the task to be ahead of schedule. Limiting the number of tasks on a Gantt chart to approximately 20 to 30 works best as including too many tasks can prove confusing. When the number exceeds more than this, one may want to divide the tasks into subtasks and generate charts for every detail level.
Figure 1 portrays a simple Gantt chart.
Figure 1: Simple Gantt Chart Example (What is a Gantt chart?, 2011).
Figure 2 depicts a more advanced Gantt chart.
Figure 2: Example of Advanced Gantt Chart (What is a Gantt chart?, 2011).
"What is a Gantt chart? (2010), further explains that the Gantt chart contains a list of the activities on the left of the chart. The top of the chart portrays a suitable time scale. A bar represents each activity; with the position and length of the bar reflecting the start date, duration and end date of the activity. This permits one to easily see:
The project's various activities
The beginning and ending time scheduled for each activity
The length of time scheduled for each activity
Points activities overlap with others as well as the amount
The entire project's start and end dates (What is a Gantt chart?, 2010).
In 1958, during the development of the Polaris Missile Project with the goal to complete this project in the shortest possible time, the U.S. Navy designed developed the PERT Chart. With approximately 3000 contractors working on the Polaris project, the application of PERT to plan and control the project helped the Navy complete the project not only within budget, but also 18 months ahead of schedule. As a project planning and control technique, PERT has become a highly favored tool for management control; with PERT serving as a crucial component of project execution, particularly in massive projects with a myriad of complex activities. "PERT has the ability to cope with uncertain activity completion times. For example, if a particular activity is most likely to be completed in 4 weeks, it could be completed anywhere between 3 weeks to 8 weeks" (Saxena, 2009, p. 179). PERT works out the expected (average) activity time based on the following three terms:
1. The most optimistic time;
2. The most pessimistic time, and
3. The most likely time.
When using the PERT formula, the project manager allocates four times more weight to the most likely time for the project's completion than to the most optimistic or most pessimistic time. The formula portrayed at the top of Figure 3 represents the estimated average activity time for the completion of the project.